Trends and disparities in the utilization of influenza vaccines among commercially insured US adults during the COVID-19 pandemic

ObjectivesLittle is known about how the coronavirus disease 2019 (COVID-19) pandemic affected influenza vaccine utilization and disparities. We sought to estimate changes in the likelihood of receiving an influenza vaccine across different demographic subgroups during the COVID-19 pandemic.MethodsIn this cohort study, we analyzed influenza vaccine uptake from 2019 to 2020 using Optum commercial insurance claims data. Eligible individuals were aged 18 or above in 2018 and continuously enrolled from 08/01/2018 through 12/31/2020. Multivariable logistic regressions were fitted for the individual-level influenza vaccine uptake. Adjusting for demographic factors and medical histories, we estimated probabilities of receiving influenza vaccines before and after the COVID-19 pandemic across demographic subgroups.ResultsFrom August to December 2019, unadjusted influenza vaccination rate was 42.3%, while in the same period of 2020, the vaccination rate increased to 45.9%. Females had a higher vaccination rate in 2019 (OR: 1.16, 95% CI 1.15–1.16), but the increase was larger for males. Blacks and Hispanics had lower vaccination rates relative to whites in both flu seasons. Hispanics showed a greater increase in vaccination rate, increasing by 7.8 percentage points (p < .001) compared to 4.4 (p < .001) for whites. The vaccination rate for Blacks increased by 5.2 percentage points (p < .001). All income groups experienced vaccination improvements, but poorer individuals had lower vaccination rates in both seasons. The most profound disparities occurred when educational cohort were considered. The vaccination rate increased among college-educated enrollees by 8.8 percentage points (p < .001) during the pandemic compared to an increase of 2.8 percentage points (p < .001) for enrollees with less than a 12th grade education. Past influenza infections or vaccination increased the likelihood of vaccination (p < .001).ConclusionsThe COVID-19 pandemic was associated with increased influenza vaccine utilization. Disparities persisted but narrowed with respect to gender and race but worsened with respect to income and educational attainment.     

The impact of seasonal influenza vaccination uptake on COVID-19 vaccination attitudes in a rural area in Greece

IntroductionPromoting vaccination for coronavirus disease 2019 (COVID-19), especially for high-risk groups such as the elderly and persons with comorbidities, is important for reducing the incidence of severe disease and death.MethodsRetrospective cross-sectional study of factors associated with COVID-19 vaccination, including previous influenza vaccination, among all persons who received medical services in a rural area in Crete, Greece, between October 2020-May 2021.ResultsAmong 3129 participants, receipt of influenza vaccination in 2020–21 was strongly associated with COVID-19 vaccination, as was influenza vaccination in 2019–20, albeit to a lesser extent. In addition, persons older than 59 years (with exception of those 90 + years old) and those who lived closer to the hospital/health center, were more likely to vaccinate for COVID-19. Persons younger than 40 years of age, females, persons with mental illness or neurologic disease, were also less likely to vaccinate for COVID-19 (all p < 0.001).ConclusionsCOVID-19 vaccination was more likely among those who were vaccinated for influenza before and during the pandemic. Access to healthcare services and specific comorbidities, were important influencers for vaccination, underlying the importance of tailored interventions to enforce vaccination in high-risk groups.     

Utilizing Google trends to monitor coronavirus vaccine interest and hesitancies

IntroductionVaccine hesitancy remains a serious challenge for ending the coronavirus disease 2019 (COVID-19) pandemic. Digital media has played an immense role in the spread of information during the pandemic. One method to gauge public interest in COVID-19 related information is to examine patterns of online search queries.MethodsGoogle Trends (GT) was used to analyze results for search terms relating to COVID-19 vaccine misinformation, information, and accessibility from October 1st, 2020 to May 27th, 2021. GT allows you to compare multiple queries at one time. The resultant relative search volumes (RSVs) range from 0 to 100. The search term and point in time on the graph that has the greatest search volume is given a score of 100 and all other terms and times are given values relative to that maximum. Search interest peaks were analyzed by subgroups (misinformation, information seeking, and access seeking) and across key time points throughout the pandemic.ResultsGT analysis revealed that search interest related to vaccine misinformation, general information, and access seeking changed in relation to events taking place throughout the pandemic. The most commonly searched terms in each subgroup were: “Covid vaccine infertility”, “Covid vaccine side effects”, and “Covid vaccine appointment”. Searches related to misinformation peaked in December 2020. Search terms in the general information category peaked in April 2021. RSVs for access seeking terms peaked in March 2021 and have decreased since April 2021.ConclusionMisinformation RSVs were highest after FDA authorization and have multiple repeated spikes after subsequent vaccine announcements. General information seeking terms peaked concurrently with increased vaccination uptake in the United States. Search interest has decreased with wider vaccine availability, despite many individuals in the United States remaining unvaccinated. GT can be used to monitor trends in public attitudes and misinformation regarding COVID-19 vaccines and further target education.     

United States Influenza Search Patterns Since the Emergence of COVID-19: Infodemiology Study

BackgroundThe emergence and media coverage of COVID-19 may have affected influenza search patterns, possibly affecting influenza surveillance results using Google Trends.ObjectiveWe aimed to investigate if the emergence of COVID-19 was associated with modifications in influenza search patterns in the United States.MethodsWe retrieved US Google Trends data (relative number of searches for specified terms) for the topics influenza, Coronavirus disease 2019, and symptoms shared between influenza and COVID-19. We calculated the correlations between influenza and COVID-19 search data for a 1-year period after the first COVID-19 diagnosis in the United States (January 21, 2020 to January 20, 2021). We constructed a seasonal autoregressive integrated moving average model and compared predicted search volumes, using the 4 previous years, with Google Trends relative search volume data. We built a similar model for shared symptoms data. We also assessed correlations for the past 5 years between Google Trends influenza data, US Centers for Diseases Control and Prevention influenza-like illness data, and influenza media coverage data.ResultsWe observed a nonsignificant weak correlation (ρ= –0.171; P=0.23) between COVID-19 and influenza Google Trends data. Influenza search volumes for 2020-2021 distinctly deviated from values predicted by seasonal autoregressive integrated moving average models—for 6 weeks within the first 13 weeks after the first COVID-19 infection was confirmed in the United States, the observed volume of searches was higher than the upper bound of 95% confidence intervals for predicted values. Similar results were observed for shared symptoms with influenza and COVID-19 data. The correlation between Google Trends influenza data and CDC influenza-like-illness data decreased after the emergence of COVID-19 (2020-2021: ρ=0.643; 2019-2020: ρ=0.902), while the correlation between Google Trends influenza data and influenza media coverage volume remained stable (2020-2021: ρ=0.746; 2019-2020: ρ=0.707).ConclusionsRelevant differences were observed between predicted and observed influenza Google Trends data the year after the onset of the COVID-19 pandemic in the United States. Such differences are possibly due to media coverage, suggesting limitations to the use of Google Trends as a flu surveillance tool.     

Influenza and pneumococcal vaccine prescription for adults during COVID-19 first wave in three regions of Argentina

Immunizations for influenza and pneumococcus are effective interventions in reducing morbidity and mortality. The objective of this study was to describe the vaccination rates in volunteers from three regions of Argentina during the COVID-19 pandemic. In 2020, 3853 adults were surveyed, 61.6 % were females, 45 % were aged between 40 and 60 and 18.6 % were > 60 years old. The commonest comorbidities were hypertension (12.9 %), dyslipidemia (8.5 %), and smokers or former smokers (9.2 %). The global influenza vaccination rate was 37.7 %, pneumococcal vaccination 24.7 %, and both 17.8 %. Multivariable regression showed that the vaccination rate increased with age and the presence of comorbidities. However, in the subgroup with indications for both vaccines, 71.7 % had the influenza vaccine, 59 % had the pneumococcal vaccine, and 28.3 % received neither. Our study suggests that influenza and pneumococcal vaccine percentages in high-risk patients in Argentina remain sub-optimal. Immunizations with proven reductions in morbimortality could have also been relegated during the COVID pandemic.     

Minimising missed opportunities to promote and deliver immunization services to middle and older age adults: Can hospital-based programs be a solution?

BackgroundThere has been a recent recognized shift towards a whole-of-life or life-course approach to immunisation. However, coverage amongst at-risk adults for recommended vaccines continues to be suboptimal. This study examined the perceptions of middle and older aged Australian adults towards hospital-based immunization programs and their previous exposures to receiving vaccines via tertiary care.MethodsA cross-sectional survey was conducted with Australian adults 45 years and older in late 2019 to capture influenza and pneumococcal vaccine uptake, exposure to hospital-based immunization programs, missed opportunities to vaccinate and receptiveness towards the promotion and/or delivery of vaccines in the hospital setting.ResultsOnly 13 respondents reported receiving a vaccine at hospital, yet 72.2% (931/1292) indicated that they were willing to be vaccinated in that setting. Amongst those who attended hospital during 2019 and were eligible for vaccination, 57.2% and 28.3% of respondents were not immunized for pneumococcal and influenza, respectively. Missed opportunities for both vaccines were significantly higher amongst those at low-risk for influenza (≤65 years (low-risk): 52.9%, ≤65 years (high-risk): 18.3%, >65 years: 15.1%; p < 0.001) and pneumococcal (≤65 years (low-risk): 79.1%, ≤65 years (high-risk): 52.4%, >65 years: 44%; p < 0.001). Among those with a missed opportunity for hospital-based vaccination, the most common reason for not getting immunized was a lack of recommendation. Most (86.4%) reported that their general practitioner was the person or group they trusted most to receive vaccine information from.ConclusionsThe findings from this Australian study support international work that shows very low rates of opportunistic vaccination in hospitals despite national recommendations to vaccinate prior to discharge. Considering the need for high levels of uptake of the COVID-19 vaccine, hospitals may need to be considered to opportunistically capture those not accessing the vaccine in other settings.     

Public perception of COVID-19 vaccines through analysis of Twitter content and users

BackgroundWith the global continuation of the COVID-19 pandemic, the large-scale administration of a SARS-CoV-2 vaccine is crucial to achieve herd immunity and curtail further spread of the virus, but success is contingent on public understanding and vaccine uptake. We aim to understand public perception about vaccines for COVID-19 through the wide-scale, organic discussion on Twitter.MethodsThis cross-sectional observational study included Twitter posts matching the search criteria ((‘covid*’ OR ‘coronavirus’) AND ‘vaccine’) posted during vaccine development from February 1st through December 11th, 2020. These COVID-19 vaccine related posts were analyzed with topic modeling, sentiment and emotion analysis, and demographic inference of users to provide insight into the evolution of public attitudes throughout the study period.FindingsWe evaluated 2,287,344 English tweets from 948,666 user accounts. Individuals represented 87.9 % (n = 834,224) of user accounts. Of individuals, men (n = 560,824) outnumbered women (n = 273,400) by 2:1 and 39.5 % (n = 329,776) of individuals were ≥40 years old. Daily mean sentiment fluctuated congruent with news events, but overall trended positively. Trust, anticipation, and fear were the three most predominant emotions; while fear was the most predominant emotion early in the study period, trust outpaced fear from April 2020 onward. Fear was more prevalent in tweets by individuals (26.3 % vs. organizations 19.4 %; p < 0.001), specifically among women (28.4 % vs. males 25.4 %; p < 0.001). Multiple topics had a monthly trend towards more positive sentiment. Tweets comparing COVID-19 to the influenza vaccine had strongly negative early sentiment but improved over time.InterpretationThis study successfully explores sentiment, emotion, topics, and user demographics to elucidate important trends in public perception about COVID-19 vaccines. While public perception trended positively over the study period, some trends, especially within certain topic and demographic clusters, are concerning for COVID-19 vaccine hesitancy. These insights can provide targets for educational interventions and opportunity for continued real-time monitoring.     

Declining influenza vaccination rates in an underserved pediatric primary care center during the COVID-19 pandemic

BackgroundInfluenza vaccination rates are decreasing in the United States. Disinformation surrounding COVID-related public health protections and SARS-CoV-2 vaccine roll-out may have unintended consequences impacting pediatric influenza vaccination. We assessed influenza vaccination rates before and during the COVID-19 pandemic in one pediatric primary care center, serving a minoritized population.MethodsA cross-sectional study assessed influenza vaccination rates for children aged 6 months to 12 years over the following influenza seasons (September-May): 1) 2018–19 and 2019–20 (pre-pandemic), and 2) 2020–21 and 2021–22 (intra-pandemic). Demographics and responses to social risk questionnaires were extracted from electronic health records. Total tetanus vaccinations across influenza seasons served as approximations of general vaccination rates. Generalized linear regression models with robust standard errors evaluated differences in demographics, social risks, and influenza vaccination rates by season. Multivariable logistic regression with robust standard errors evaluated associations between influenza season, demographics, social risks, and influenza vaccination.ResultsMost patients were young (mean age ～ 6 years), non-Hispanic Black (～80%), and publicly insured (～90%). Forty-two percent of patients eligible to receive the influenza vaccine who were seen in 2019–20 influenza season received the influenza vaccine, compared to 30% in 2021–22. Influenza and tetanus vaccination rates decreased during the COVID-19 pandemic (p < 0.01). The 2020–21 and 2021–22 influenza seasons, older age, Black race, and self-pay were associated with decreased influenza vaccine administration (p < 0.05).ConclusionsInfluenza vaccination rates within one pediatric primary care center decreased during the COVID-19 pandemic and have not rebounded, particularly for older children, those identifying as Black, and those without insurance.     

A validated modification of the vaccine hesitancy scale for childhood,influenza and HPV vaccines

IntroductionVaccine hesitancy contributes to outbreaks of preventable disease worldwide. The Vaccine Hesitancy Scale (VHS), developed by the international WHO SAGE Working Group, has been validated previously for measuring hesitancy towards childhood vaccines; some psychometric properties were suboptimal.MethodsWe collected data using large, nationally-representative samples of parents in the U.S. We adapted the VHS items, and additional hesitancy items, to assess hesitancy towards influenza and HPV vaccines in addition to routine childhood vaccines. We then used exploratory and confirmatory factor analysis to identify latent constructs and create modified scales for childhood (VHS-child), influenza (VHS-flu) and HPV (VHS-HPV) vaccines with improved psychometric properties. Finally, we compared hesitancy scores on the VHS-child, VHS-flu, and VHS-HPV, to self-reported receipt of each vaccine category, and compared subscale scores to assess whether drivers of hesitancy differed by vaccine category.Results2052 parents of children <18 years old completed the VHS-child and VHS-flu while 2020 parents of adolescents completed the VHS-HPV. A two-factor structure of ‘risks’ and a ‘lack of confidence’ was found for each vaccine category. Slight modifications to the VHS improved psychometric properties. Hesitancy was strongly associated with vaccine receipt: e.g., 76% of parents not hesitant towards influenza vaccine had vaccinated their child the past season, versus 9% of hesitant parents (p < 0.0001). Subscale scores also differed significantly between vaccines: lack of confidence was greater towards influenza (Median (IQR): 2.0 (1.2, 3.3)) and HPV (2.0 (1.3, 3.0)) vaccines than childhood (1.2 (1.0, 1.8), p < 0.0001 for both) vaccines; perceived risks of HPV vaccines (2.7 (1.7, 3.7)) were greater than for childhood vaccines (2.0 (1.3, 3.0), p < 0.0001).ConclusionsOur modified VHS scales perform well psychometrically and allow for consistent measurement of the extent and reasons for hesitancy between vaccine categories. We suggest that future work use these scales to examine hesitancy towards other vaccines and to monitor hesitancy over time.     

Safety of co-administration of mRNA COVID-19 and seasonal inactivated influenza vaccines in the vaccine adverse event reporting system (VAERS) during July 1, 2021–June 30, 2022

BackgroundCOVID-19 vaccines may be co-administered with other recommended vaccines, including seasonal influenza vaccines. However, few studies have evaluated the safety of co-administration of mRNA COVID-19 and seasonal influenza vaccines.ObjectiveTo describe reports to the Vaccine Adverse Event Reporting System (VAERS) after co-administration of mRNA COVID-19 and seasonal influenza vaccines.MethodsWe searched the VAERS database for reports of adverse events (AEs) following co-administration of mRNA COVID-19 and seasonal influenza vaccines and following a first booster dose mRNA COVID-19 vaccine alone, during July 1, 2021–June 30, 2022. We assessed the characteristics of these reports and described the most frequently reported MedDRA preferred terms (PTs). Clinicians reviewed available medical records for serious reports and reports of adverse events of special interest (AESI) and categorized the main diagnosis by system organ class.ResultsFrom July 1, 2021 through June 30, 2022, VAERS received 2,449 reports of adverse events following co-administration of mRNA COVID-19 and seasonal influenza vaccines. Median age of vaccinees was 48 years (IQR: 31, 66); 387 (15.8%) were classified as serious. Most reports (1,713; 69.3%) described co-administration of a first booster dose of an mRNA COVID-19 vaccine with seasonal influenza vaccine. The most common AEs among non-serious reports were injection site reactions (193; 14.5%), headache (181; 13.6%), and pain (171; 12.8%). The most common AEs among reports classified as serious were dyspnea (38; 14.9%), COVID-19 infection (32; 12.6%), and chest pain (27; 10.6%).DiscussionThis review of reports to VAERS following co-administration of mRNA COVID-19 and seasonal influenza vaccines did not reveal any unusual or unexpected patterns of AEs. Increased reporting of certain events (e.g., COVID-19 disease) was expected. CDC will continue to monitor the safety of co-administration of mRNA COVID-19 and seasonal influenza vaccines, including co-administration involving bivalent mRNA COVID-19 booster vaccines that have been recommended for people ages ≥ 6 months in the United States.     

Influenza and pneumococcal vaccinations are not associated to COVID-19 outcomes among patients admitted to a university hospital

In order to reduce the burden on healthcare systems and to support differential diagnosis with COVID-19, influenza and pneumococcal vaccinations were strongly recommended during the COVID-19 pandemic, especially in vulnerable groups. However, no univocal and conclusive evidence on the relationship between influenza and pneumococcal vaccinations and COVID‐19 outcomes exists. We evaluated the association between such vaccinations, COVID-19 hospitalization, intensive care unit admissions and deaths in a cohort (N = 741) of COVID-19 patients who had access to the emergency room of a large Italian University hospital between March 1, 2020 and June 1, 2020. Results show that influenza and pneumococcal vaccinations did not affect hospitalization, intensive care unit admission and deaths in COVID-19 patients in the overall sample and in those ≥65 years. The same pattern of results was confirmed considering timing of influenza vaccine administration, vaccination type, and number of uptakes in the last five vaccination campaigns. In conclusion, our study does not support an impact of influenza and pneumococcal vaccinations on COVID-19 outcomes.     

The impact of the COVID-19 pandemic on parents’ perceptions and acceptance of routine childhood vaccination in Canada: A national longitudinal study

BackgroundA decline in routine vaccination was reported by some countries early in the COVID-19 pandemic. In the context of the pandemic, determinants of routine childhood vaccination may have changed. Changes over time in parents’ perceptions of routine vaccines and intentions for their children during the pandemic have not been fully explored. Understanding changes provides opportunities to promote routine childhood vaccines and address factors that may compromise parents’ acceptance.MethodsWe conducted longitudinal analysis of two sequential national surveys during the pandemic (Dec 2020 and Oct/Nov 2021) to assess changes over time in Canadian parents’ perceptions of routine childhood vaccines, intentions to vaccinate, access for their children ≤ 17 years, and differences among sociodemographic characteristics. McNemar-Bowker tests were used to determine changes in parents’ responses collected at two time points.ResultsOf the 650 parents in the sample, 25.1% with a child ≤ 6 years and 20.5% with a child 7–17 years perceived that routine childhood vaccines were more important because of the pandemic. Between the two time points, parents’ confidence in the safety (72.8% to 80.2%, p <.001) and effectiveness (81.7% to 85.2%, p =.007) of routine vaccines increased, parents were more engaged in vaccine decision-making (73.4% to 79.8%, p =.006), and everyday stress preventing vaccination decreased (78.8% to 68.5%, p <.001). Acceptance of routine vaccines increased (82.9% to 86.5%, p =.021), but more parents were undecided about influenza vaccination (12.6% to 20.3%, p =.002). Compared to parents with 1 child, those with 2 children reported increased vaccination acceptance (82.6% to 87.4%, p =.024).InterpretationUnder the spotlight of COVID-19, parents’ confidence in routine vaccines, engagement in decision-making, and vaccination acceptance increased. Vaccination providers should support parents’ decision-making as they navigate routine childhood vaccine uncertainties. Differences in parents’ acceptance of routine and influenza vaccines for their children highlight the need for targeted communication strategies for specific vaccines.     

Background rates of all-cause mortality,hospitalizations, and emergency department visits among nursing home residents in Ontario,Canada to inform COVID-19 vaccine safety assessments

BackgroundNursing home (NH) residents are prioritized for COVID-19 vaccination. We report monthly mortality, hospitalizations, and emergency department (ED) visit incidence rates (IRs) during 2010–2020 to provide context for COVID-19 vaccine safety assessments.MethodsWe observed outcomes among all NH residents in Ontario using administrative databases. IRs were calculated by month, sex, and age group. Comparisons between months were assessed using one-sample t-tests; comparisons by age and sex were assessed using chi-squared tests.ResultsFrom 2010 to 2019, there were 83,453 (SD: 652.4) NH residents per month, with an average of 2.3 (SD: 0.28) deaths, 3.1 (SD: 0.16) hospitalizations, and 3.6 (SD: 0.17) ED visits per 100 residents per month. From March to December 2020, mortality IRs were increased, but hospitalization and ED visit IRs were reduced (p < 0.05).ConclusionWe identified consistent monthly mortality, hospitalization, and ED visit IRs during 2010–2019. Marked differences in these rates were observed during 2020, coinciding with the COVID-19 pandemic.     

Safety of simultaneous vaccination with COVID-19 vaccines in the Vaccine Safety Datalink

IntroductionSafety data on simultaneous vaccination (SV) with primary series monovalent COVID-19 vaccines and other vaccines are limited. We describe SV with primary series COVID-19 vaccines and assess 23 pre-specified health outcomes following SV among persons aged ≥5 years in the Vaccine Safety Datalink (VSD).MethodsWe utilized VSD’s COVID-19 vaccine surveillance data from December 11, 2020-May 21, 2022. Analyses assessed frequency of SV. Rate ratios (RRs) were estimated by Poisson regression when the number of outcomes was ≥5 across both doses, comparing outcome rates between COVID-19 vaccinees receiving SV and COVID-19 vaccinees receiving no SV in the 1–21 days following COVID-19 vaccine dose 1 and 1–42 days following dose 2 by SV type received (“All SV”, “Influenza SV”, “Non-influenza SV”).ResultsSV with COVID-19 vaccines was not common practice (dose 1: 0.7 % of 8,455,037 persons, dose 2: 0.3 % of 7,787,013 persons). The most frequent simultaneous vaccines were influenza, HPV, Tdap, and meningococcal. Outcomes following SV with COVID-19 vaccines were rare (total of 56 outcomes observed after dose 1 and dose 2). Overall rate of outcomes among COVID-19 vaccinees who received SV was not statistically significantly different than the rate among those who did not receive SV (6.5 vs. 6.8 per 10,000 persons). Statistically significant elevated RRs were observed for appendicitis (2.09; 95 % CI, 1.06–4.13) and convulsions/seizures (2.78; 95 % CI, 1.10–7.06) in the “All SV” group following dose 1, and for Bell’s palsy (2.82; 95 % CI, 1.14–6.97) in the “Influenza SV” group following dose 2.ConclusionCombined pre-specified health outcomes observed among persons who received SV with COVID-19 vaccine were rare and not statistically significantly different compared to persons who did not receive SV with COVID-19 vaccine. Statistically significant adjusted rate ratios were observed for some individual outcomes, but the number of outcomes was small and there was no adjustment for multiple testing.     

Factors associated with pneumococcal vaccine uptake among vulnerable older adults in the United States primary care setting

Pneumococcal vaccine uptake targets set by Healthy People 2020 were not met by 2019 among vulnerable United States populations, yet research suggests progress can be made in primary care settings. This study assessed factors associated with having gotten a pneumococcal vaccine among vulnerable adults aged 50 and older. This study used the 2018 Medical Expenditure Panel Survey nationally representative dataset. Eligible individuals were aged 50–64 with an ‘at risk’ health condition or ≥65 years and had a primary care provider as their usual source of care (N = 3,760). Binary logistic regression was used to test factors (identified from literature) for a significant association with getting the pneumococcal vaccine. Factors with significant associations were entered into an adjusted multivariable logistic regression model to generate the odds of endorsing a factor given that the respondent got the vaccine. Collinearity among variables was examined with an unacceptable threshold of 0.8 correlation. A significance threshold of 0.05 was used. Those who got the pneumococcal vaccine had 16.7 (p < 0.001), 16.0 (p < 0.001) and 11.0 times (p < 0.001) higher odds of having also gotten the influenza vaccine, the herpes zoster vaccine and a colonoscopy respectively. They had 3.86 times (p = 0.009) higher odds of having diabetes mellitus, 0.036 times (p = 0.019) higher odds of having visited their doctors three times in 2018 and 8.4 times (p = 0.009) higher odds of having seen their doctor within the last year. Concordance statistic for model fit was 0.936. There was a negative association between pneumococcal vaccination and going to three doctor office visits in 2018 vs only once. The strongest positive associations were found between pneumococcal vaccination and getting the herpes zoster vaccine, influenza vaccine and getting a colonoscopy. These results suggest that those who choose to get the pneumococcal vaccine may have higher odds of also getting other vaccines or specific preventative screenings.     

Intention of nurses to accept coronavirus disease 2019 vaccination and change of intention to accept seasonal influenza vaccination during the coronavirus disease 2019 pandemic: A cross-sectional survey

BackgroundMaintaining health of healthcare workers with vaccination is a major component of pandemic preparedness and acceptance of vaccinations is essential to its success. This study aimed to examine impact of the coronavirus disease 2019 (COVID-19) pandemic on change of influenza vaccination acceptance and identify factors associated with acceptance of potential COVID-19 vaccination.MethodA cross-sectional self-administered anonymous questionnaire survey was conducted among nurses in Hong Kong, China during 26 February and 31 March 2020. Their previous acceptance of influenza vaccination and intentions to accept influenza and COVID-19 vaccination were collected. Their relationship with work-related and other factors were examined using multiple multinomial logistic regressions.ResultsResponses from 806 participants were retrieved. More nurses changed from vaccination refusal to hesitancy or acceptance than those changed from acceptance to vaccination hesitancy or refusal (15.5% vs 6.8% among all participants, P < 0.001). 40.0% participants intended to accept COVID-19 vaccination, and those in private sector (OR: 1.67, 95%CI: 1.11–2.51), with chronic conditions (OR: 1.83, 95%CI: 1.22–2.77), encountering with suspected or confirmed COVID-19 patients (OR: 1.63, 95%CI: 1.14–2.33), accepted influenza vaccination in 2019 (OR: 2.03, 95%CI: 1.47–2.81) had higher intentions to accept it. Reasons for refusal and hesitation for COVID-19 vaccination included “suspicion on efficacy, effectiveness and safety”, “believing it unnecessary”, and “no time to take it”.ConclusionWith a low level of COVID-19 acceptance intentions and high proportion of hesitation in both influenza and COVID-19 vaccination, evidence-based planning are needed to improve the uptake of both vaccinations in advance of their implementation. Future studies are needed to explore reasons of change of influenza vaccination acceptance, look for actual behaviour patterns of COVID-19 vaccination acceptance and examine effectiveness of promotion strategies.     

Veteran influenza vaccination acceptance rates after completion of the COVID-19 vaccination series among historical influenza vaccine refusers

BackgroundVaccine hesitancy remains an obstacle in disease prevention. The recent COVID-19 pandemic highlighted this issue and may influence acceptance of other recommended immunizations. The objective of this study was to determine the association between receiving the COVID-19 vaccination and the subsequent acceptance of the influenza vaccination in a Veteran population that historically declined influenza vaccination.MethodsInfluenza vaccination acceptance rates for the 2021–2022 influenza season were compared in patients who historically declined the influenza vaccine and either received or declined COVID-19 vaccinations. Logistic regression analysis was used to analyze factors associated with receiving influenza vaccination among vaccine hesitant individuals.ResultsA higher proportion of patients who had received the COVID-19 vaccination(s) subsequently accepted the influenza vaccination compared to the control group (37% vs. 11%, OR = 5.03; CI 3.15–8.26; p = 0.0001).ConclusionAmong previous influenza vaccine decliners, those who received COVID-19 vaccination had significantly higher odds of receiving subsequent influenza vaccination.     

Safety of components and platforms of COVID-19 vaccines considered for use in pregnancy: A rapid review

BackgroundRapid assessment of COVID-19 vaccine safety during pregnancy is urgently needed.MethodsWe conducted a rapid systematic review, to evaluate the safety of COVID-19 vaccines selected by the COVID-19 Vaccines Global Access-Maternal Immunization Working Group in August 2020, including their components and their technological platforms used in other vaccines for pregnant persons. We searched literature databases, COVID-19 vaccine pregnancy registries, and explored reference lists from the inception date to February 2021 without language restriction. Pairs of reviewers independently selected studies through COVIDENCE, and performed the data extraction and the risk of bias assessment. Discrepancies were resolved by consensus. Registered on PROSPERO (CRD42021234185).ResultsWe retrieved 6757 records and 12 COVID-19 pregnancy registries from the search strategy; 38 clinical and non-clinical studies (involving 2,398,855 pregnant persons and 56 pregnant animals) were included. Most studies (89%) were conducted in high-income countries and were cohort studies (57%). Most studies (76%) compared vaccine exposures with no exposure during the three trimesters of pregnancy. The most frequent exposure was to AS03 adjuvant, in the context of A/H1N1 pandemic influenza vaccines, (n = 24) and aluminum-based adjuvants (n = 11). Only one study reported exposure to messenger RNA in lipid nanoparticles COVID-19 vaccines. Except for one preliminary report about A/H1N1 influenza vaccination (adjuvant AS03), corrected by the authors in a more thorough analysis, all studies concluded that there were no safety concerns.ConclusionThis rapid review found no evidence of pregnancy-associated safety concerns of COVID-19 vaccines or of their components or platforms when used in other vaccines. However, the need for further data on several vaccine platforms and components is warranted, given their novelty. Our findings support current WHO guidelines recommending that pregnant persons may consider receiving COVID-19 vaccines, particularly if they are at high risk of exposure or have comorbidities that enhance the risk of severe disease.     

Changes in the incidence of seasonal influenza in response to COVID-19 social distancing measures: an observational study based on Canada’s national influenza surveillance system

ObjectivesSeasonal influenza is an acute respiratory infection that presents a significant annual burden to Canadians and the Canadian healthcare system. Social distancing measures that were implemented to control the 2019–2020 novel coronavirus outbreak were investigated for their ability to lessen the incident cases of seasonal influenza.MethodsWe conducted an ecological study using data from Canada’s national influenza surveillance system to investigate whether social distancing measures to control COVID-19 reduced the incident cases of seasonal influenza. Data taken from three separate time frames facilitated analysis of the 2019–2020 influenza season prior to, during, and following the implementation of COVID-19-related measures and enabled comparisons with the same time periods during three preceding flu seasons. The incidence, which referred to the number of laboratory-confirmed cases of specific influenza strains, was of primary focus. Further analysis determined the number of new laboratory-confirmed influenza or influenza-like illness outbreaks.ResultsOur results indicate a premature end to the 2019–2020 influenza season, with significantly fewer cases and outbreaks being recorded following the enactment of many COVID-19 social distancing policies. The incidence of influenza strains A (H3N2), A (unsubtyped), and B were all significantly lower at the tail end of the 2019–2020 influenza season as compared with preceding seasons (p = 0.0003, p = 0.0007, p = 0.0019).ConclusionSpecific social distancing measures and behaviours may serve as effective tools to limit the spread of influenza transmission moving forward, as they become more familiar.Supplementary InformationThe online version contains supplementary material available at 10.17269/s41997-021-00509-4.     

Serious adverse events of special interest following mRNA COVID-19 vaccination in randomized trials in adults

IntroductionIn 2020, prior to COVID-19 vaccine rollout, the Brighton Collaboration created a priority list, endorsed by the World Health Organization, of potential adverse events relevant to COVID-19 vaccines. We adapted the Brighton Collaboration list to evaluate serious adverse events of special interest observed in mRNA COVID-19 vaccine trials.MethodsSecondary analysis of serious adverse events reported in the placebo-controlled, phase III randomized clinical trials of Pfizer and Moderna mRNA COVID-19 vaccines in adults (NCT04368728 and NCT04470427), focusing analysis on Brighton Collaboration adverse events of special interest.ResultsPfizer and Moderna mRNA COVID-19 vaccines were associated with an excess risk of serious adverse events of special interest of 10.1 and 15.1 per 10,000 vaccinated over placebo baselines of 17.6 and 42.2 (95 % CI ?0.4 to 20.6 and ?3.6 to 33.8), respectively. Combined, the mRNA vaccines were associated with an excess risk of serious adverse events of special interest of 12.5 per 10,000 vaccinated (95 % CI 2.1 to 22.9); risk ratio 1.43 (95 % CI 1.07 to 1.92). The Pfizer trial exhibited a 36 % higher risk of serious adverse events in the vaccine group; risk difference 18.0 per 10,000 vaccinated (95 % CI 1.2 to 34.9); risk ratio 1.36 (95 % CI 1.02 to 1.83). The Moderna trial exhibited a 6 % higher risk of serious adverse events in the vaccine group: risk difference 7.1 per 10,000 (95 % CI –23.2 to 37.4); risk ratio 1.06 (95 % CI 0.84 to 1.33). Combined, there was a 16 % higher risk of serious adverse events in mRNA vaccine recipients: risk difference 13.2 (95 % CI ?3.2 to 29.6); risk ratio 1.16 (95 % CI 0.97 to 1.39).DiscussionThe excess risk of serious adverse events found in our study points to the need for formal harm-benefit analyses, particularly those that are stratified according to risk of serious COVID-19 outcomes. These analyses will require public release of participant level datasets.