Influenza vaccination uptake among Canadian adults before and during the COVID-19 pandemic: An analysis of the Canadian Longitudinal study on Aging (CLSA)

IntroductionUnderstanding how influenza vaccine uptake changed during the 2020/2021 influenza season compared to previous pre-pandemic seasons is a key priority, as is identifying the relationship between prior influenza vaccination and COVID-19 vaccine willingness.MethodsWe analyzed data from a large, nationally representative cohort of Canadian residents aged 50 and older to assess influenza vaccination status three times between 2015 and 2020. We investigated: 1) changes in self-reported influenza vaccine uptake, 2) predictors of influenza vaccine uptake in 2020/2021, and 3) the association between influenza vaccination history and self-reported COVID-19 vaccine willingness using logistic regression models.ResultsAmong 23,385 participants analyzed for aims 1–2, influenza vaccination increased over time: 14,114 (60.4%) in 2015–2018, 15,692 (67.1%) in 2019/2020, and 19,186 (82.0%; combining those already vaccinated and those planning to get a vaccine) in 2020/2021. After controlling for socio-demographics, history of influenza vaccination was most strongly associated with influenza vaccination in 2020/2021 (adjusted odds ratio [aOR] 147.9 [95% CI: 120.9–180.9]); this association remained after accounting for multiple health and pandemic-related factors (aOR 140.3 [95% CI: 114.5–171.8]). To a lesser degree, those more concerned about COVID-19 were also more likely to report influenza vaccination in fall 2020, whereas those reporting a very negative impact of the pandemic were less likely to get vaccinated. Among 23,819 participants with information on COVID-19 vaccine willingness during the last quarter of 2020 (aim 3), prior influenza vaccination was most strongly associated with willingness to get a COVID-19 vaccine (aOR 15.1 [95% CI: 13.5–16.8] for those who had received influenza vaccine at all previous timepoints versus none).ConclusionsOur analysis highlights the importance of previous vaccination in driving vaccination uptake and willingness. Efforts to increase vaccination coverage for influenza and COVID-19 should target individuals who do not routinely engage with immunization services regardless of demographic factors.     

Does consecutive influenza vaccination reduce protection against influenza: A systematic review and meta-analysis

IntroductionVaccination against influenza on an annual basis is widely recommended, yet recent studies suggest consecutive vaccination may reduce vaccine effectiveness (VE).PurposeTo assess whether when examining the entirety of existing data consecutive influenza vaccination reduces VE compared to current season influenza vaccination.Data sourcesMEDLINE, EMBASE and the Cochrane Central Register of Controlled Trials (CENTRAL) from inception to April 26, 2017; citations of included studies.Study selectionRandomized, controlled trials (RCTs) and observational studies of children, adults and/or the elderly that reported laboratory-confirmed influenza infection over 2 or more consecutive influenza seasons were eligible.Data extractionData related to study characteristics, participant demographics, cases of influenza infection by vaccination group and risk of bias assessment was extracted in duplicate.Data synthesisFive RCTs involving 11,987 participants did not show a significant reduction in VE when participants vaccinated in two consecutive seasons (VE 71%, 95% CI 62–78%) were compared to those vaccinated in the current season (VE 58%, 95% CI 48–66%) (odds ratio [OR] 0.88, 95% CI 0.62–1.26, p = 0.49, I² = 39%). Twenty-eight observational studies involving 28,627 participants also did not show a reduction (VE for two consecutive seasons 41%, 95% CI 30–51% compared to VE for current season 47%, 95% CI 39–54%; OR 1.14, 95% CI 0.98–1.32, p = 0.09, I² = 63%). Results from subgroup analyses by influenza type/subtype, vaccine type, age, vaccine match and co-morbidity support these findings; however, dose–response results were inconsistent. Certainty in the evidence was assessed to be very low due to unexplained heterogeneity and imprecision.LimitationsThe inclusion of studies with relatively small sample sizes and low event rates contributed to the imprecision of summary VE and OR estimates, which were based on unadjusted data.ConclusionAvailable evidence does not support a reduction in VE with consecutive influenza vaccination, but the possibility of reduced effectiveness cannot be ruled out due to very low certainty in this evidence.Funding sourceCIHR Foundation Grant (PROSPERO: CRD42017059893).     

Effectiveness of the current and prior influenza vaccinations in Northern Spain, 2018–2019

BackgroundThe population targeted for influenza vaccination can be repeatedly vaccinated over successive seasons, and vaccines received in previous seasons may retain preventive effect. This study aims to estimate the effectiveness of inactivated influenza vaccines received in the current and prior seasons in the 2018–2019 season.MethodsInfluenza-like illness patients attended by sentinel general practitioners or admitted to hospitals in Navarre, Spain, were tested for influenza. Vaccination status in the current and three prior seasons was obtained from the vaccination registry. The test-negative design was used to estimate the vaccine effectiveness.ResultsA total of 381 influenza A(H1N1)pdm09 cases, 341 A(H3N2) cases and 1222 controls were analysed. As compared to individuals unvaccinated in the current and three prior seasons, the influenza vaccine effectiveness against A(H1N1)pdm09 was 57% (95% confidence interval [CI]: 40%, 70%) for current season vaccination regardless of prior doses and 48% (95%CI: 14%, 68%) for vaccination in prior seasons but not in the current season. These estimates were 12% (95%CI: −23%, 37%) and 27% (95%CI: −22%, 56%), respectively, against influenza A(H3N2). Individuals vaccinated with the two A(H1N1)pdm09 strains in influenza vaccines since 2009, A/Michigan/45/2015 and A/California/07/2009, had higher protection (68%; 95%CI: 53%, 77%) than those vaccinated with A/Michigan/45/2015 only (29%, p = 0.020) or with A/California/07/2009 only (34%, p = 0.005).ConclusionThese results suggest moderate effectiveness of influenza vaccination against A(H1N1)pdm09 and low effectiveness against A(H3N2) influenza in the 2018–2019 season. Vaccination in prior seasons maintained a notable protective effect. Strains included in previous vaccines were as effective as the current vaccine strain, and both added their effects against influenza A(H1N1)pdm09.     

Factors affecting parental intention to vaccinate kindergarten children against influenza: A cross-sectional survey in China

Background

The impact of influenza in children under 5 can be severe and fatal. However, the influenza vaccination uptake in China remains suboptimal. The objectives of this study were to investigate parents’ perceptions on influenza vaccination and to assess vaccination promotional factors.

Association between seasonal influenza vaccination with pre- and postnatal outcomes

Objective

Influenza vaccination during pregnancy is known to prevent severe influenza illness but its effects on other outcomes and the extent to which its safety is affected by timing of vaccination, maternal race/ethnicity and the type of vaccine is less clear. Therefore, we examined this in a large retrospective cohort.

Multimorbidity is associated with uptake of influenza vaccination

ObjectivePatients with chronic conditions have higher rates of severe influenza-related illness and mortality. However, influenza vaccination coverage in high-risk populations continues to be suboptimal. We describe the association between cumulative disease morbidity, measured by a previously validated multimorbidity index, and influenza vaccination among community-dwelling adults.MethodsWe obtained interview and medical record data for participants ≥18 years who sought outpatient care for influenza-like illness between 2011 and 2016 as part of an outpatient-based study of influenza vaccine effectiveness. We defined cumulative disease morbidity by using medical diagnosis codes to calculate a multimorbidity-weighted index (MWI) for each participant. MWI and influenza vaccination status was evaluated by logistic regression. Akaike information criterion was calculated for all models.ResultsOverall, 1458 (48%) of participants out of a total of 3033 received influenza vaccination. The median MWI was 0.9 (IQR 0.00–3.5) and was higher among vaccinated participants (median 1.6 versus 0.0; p < 0.001). We found a positive linear association between MWI and vaccination, and vaccination percentages were compared between categories of MWI. Compared to patients with no multimorbidity (MWI = 0), odds of vaccination were 17% higher in the second category (MWI 0.01–1.50; [OR: 1.17, 95% CI: 0.92–1.50]), 58% higher in the third category (MWI 1.51–3.00; [OR: 1.58, 95% CI: 1.26–1.99]), 130% higher in the fourth category (MWI 3.01–6.00; [OR: 2.30, 95% CI: 1.78–2.98]) and 214% higher in the fifth category (MWI 6.01–45.00;[OR: 3.14, 95% CI: 2.41–4.10]). Participants defined as high-risk had 86% greater odds of being vaccinated than non-high-risk individuals (OR: 1.86, 95% CI: 1.56–2.21). The AIC was lowest for MWI compared with high-risk conditions.ConclusionsOur results suggest a dose response relationship between level of multimorbidity and likelihood of influenza vaccination. Compared with high-risk condition designations, MWI provided improved precision and a better model fit for the measurement of chronic disease and influenza vaccination.     

A multi-country investigation of influenza vaccine coverage in pregnant individuals, 2010–2016

BackgroundMany countries recommend influenza vaccination during pregnancy. Despite this recommendation, influenza vaccine among pregnant individuals remains under-utilized and uptake varies by country. Factors associated with influenza vaccine uptake during pregnancy may also vary across countries.MethodsAs members of the Pregnancy Influenza Vaccine Effectiveness Network (PREVENT), five sites from four countries (Australia, Canada, Israel, and the United States) retrospectively identified cohorts of individuals aged 18–50 years who were pregnant during pre-defined influenza seasons. Influenza vaccine coverage estimates were calculated for the 2010–11 through 2015–16 northern hemisphere and the 2012 through 2015 southern hemisphere influenza seasons, by site. Sites used electronic health records, administrative data, and immunization registries to collect information on pregnancy, health history, demographics, and vaccination status. Each season, vaccination coverage was calculated as the percentage of individuals who received influenza vaccine among the individuals in the cohort that season. Characteristics were compared between those vaccinated and unvaccinated, by site.ResultsMore than two million pregnancies were identified over the study period. Influenza vaccination coverage ranged from 5% to 58% across sites and seasons. Coverage increased consistently over the study period at three of the five sites (Western Australia, Alberta, and Israel), and was highest in all seasons at the United States study site (39–58%). Associations with vaccination varied by country and across seasons; where available, parity >0, presence of a high-risk medical condition, and urban residence were consistently associated with increased likelihood of vaccination.ConclusionsThough increasing, uptake of influenza vaccine among pregnant individuals remains lower than recommended. Coverage varied substantially by country, suggesting an ongoing need for targeted strategies to improve influenza vaccine uptake in this population.     

Role of social determinants of health in pneumococcal vaccination among high-risk adults

ObjectivesTo determine the influence of select social determinants of health on uptake of and time to pneumococcal vaccination among those deemed high-risk.MethodsUsing nationwide claims data for years 2013–2016, adult patients (aged 18–64 years) were followed from their first diagnosis for a condition deeming them high-risk for invasive pneumococcal disease through the subsequent 365 days and observed for pneumococcal vaccination in outpatient clinics and pharmacies. Publicly-available data on select social determinants of health were incorporated into analyses, guided by the WHO vaccine hesitancy matrix. Controlling for baseline demographic and clinical characteristics, logistic regression determined predictors of vaccination and a general linear model compared days to being vaccinated.ResultsA total of 173,712 patients were analyzed of which approximately one quarter (25.3%) were vaccinated against invasive pneumococcal disease within the first year of being deemed high risk, nearly all of which (98.5%) were received in outpatient clinics. The odds of vaccination were higher among urban residents (OR: 1.18; 95% CI: 1.144–1.223), areas of higher health literacy (OR: 1.02; 95% CI: 1.019–1.025), and more Democratic-voting communities (OR: 1.5; 95% CI: 1.23–1.88). Conversely, the likelihood of vaccination was particularly low in areas of higher poverty (OR: 0.14; 95% CI: 0.068–0.304) and with limited Internet access (OR: 0.14; 95% CI: 0.062–0.305) as well as among adults who did not also get a seasonal influenza vaccine (OR: 0.05; 95% CI: 0.048–0.052). Time to vaccination was longer in rural residents (B = 8.3, p < 0.0001) and communities with less Internet access (B = 75.6, p < 0.001).ConclusionSocial determinants may be influencing pneumococcal vaccine-seeking behavior among those deemed high-risk, but a more formal and comprehensive framework must be assessed to determine the full impact of these factors across vaccines recommended in adults.     

Influence of family on acceptance of influenza vaccination among Japanese patients

BACKGROUND: Influenza is a major cause of morbidity and mortality in Japan and worldwide, especially for people of >65 years old and those with high-risk medical conditions. Although the influenza vaccine is effective in reducing the morbidity and mortality, the vaccine coverage rate has not increased adequately in Japan, compared with western countries. OBJECTIVE: Our aim was to assess whether medical and personal characteristics are associated with receiving influenza vaccination in Japanese patients. METHODS: Out-patients of a city hospital were recruited for a case-control study between November 1998 and February 1999. Cases were 98 out-patients aged 18 years or older who received influenza vaccination. Controls were 112 non-vaccinated out-patients matched with cases for primary physician and date of clinic visit. The candidates were interviewed by telephone and asked to respond to a 26-item questionnaire. The data were analysed using multiple logistic regression models. RESULTS: The factors associated with the acceptance of influenza vaccination were: (i) recommendation by a family member and/or a close friend [odds ratio (OR) 17.74; 95% confidence interval (CI) 1.95-161.77]; (ii) belief in influenza vaccine efficacy (OR 10.55; 95% CI 3.42-32.49); (iii) having a family member and/or friends who had been vaccinated before (OR 6.44; 95% CI 2.37-17.50); (iv) physician's recommendation (OR 4.03; 95% CI 1.42-11.37); and (v) knowledge about the influenza vaccine (OR 3.06; 95% CI 1.02-9.20). Fear of adverse reactions (OR 0.21; 95% CI 0.07-0.66) was the sole factor associated with non-acceptance of influenza vaccine. CONCLUSION: Patients in Japan are likely to be greatly influenced by their family members or close friends in their decision of whether to accept influenza vaccination, unlike US patients who make health care decisions on their own. When implementing an influenza vaccination programme, this effect of cultural background observed in Japan should be taken into account in other countries.     

Low vaccination coverage for seasonal influenza and pneumococcal disease among adults at-risk and health care workers in Ireland, 2013: The key role of GPs in recommending vaccination

The World Health Organization (WHO), and European Agencies recommend influenza vaccination for individuals at-risk due to age (≥65 years), underlying diseases, pregnancy and for health care workers (HCWs) in Europe. Pneumococcal vaccine is recommended for those at-risk of pneumococcal disease. In Ireland, vaccination uptake among at-risk adults is not routinely available. In 2013, we conducted a national survey among Irish residents ≥18 years of age, to estimate size and vaccination coverage of at-risk groups, and identify predictive factors for influenza vaccination.We used computer assisted telephone interviews to collect self-reported information on health, vaccination status, attitudes towards vaccination. We calculated prevalence and prevalence ratios (PR) using binomial regression.Overall, 1770 individuals participated. For influenza, among those aged 18–64 years, 22% (325/1485) [95%CI: 17%–20%] were at-risk; 28% [95%CI: 23%–33%] were vaccinated. Among those aged ≥65 years, 60% [95%CI: 54%–66%] were vaccinated. Influenza vaccine uptake among HCWs was 28% [95%CI: 21%–35%]. For pneumococcal disease, among those aged 18–64 years, 18% [95%CI: 16%–20%] were at-risk; 16% [95%CI: 12%–21%] reported ever-vaccination; among those aged ≥65 years, 36% [95%CI: 30%–42%] reported ever-vaccination. Main reasons for not receiving influenza vaccine were perceptions of not being at-risk, or not thinking of it; and among HCWs thinking that vaccination was not necessary or they were not at-risk. At-risk individuals were more likely to be vaccinated if their doctor had recommended it (PR 3.2; [95%CI: 2.4%-4.4%]) or they had access to free medical care or free vaccination services (PR 2.0; [95%CI: 1.5%-2.8%]).Vaccination coverage for both influenza and pneumococcal vaccines in at-risk individuals aged 18–64 years was very low. Influenza vaccination coverage among individuals ≥65 years was moderate. Influenza vaccination status was associated with GP vaccination recommendation and free access to vaccination services. Doctors should identify and recommend vaccination to at-risk patients to improve uptake.     

Reduced efficiency of influenza vaccine in prevention of influenza-like illness in working adults: a 7 month prospective survey in EDF Gaz de France employees,in Rhône-Alpes, 1996-1997

The efficiency of influenza vaccine was evaluated in the working population by comparing the percentage of people presenting with an influenza-like illness (ILI) according to their influenza immunization status, drug expenses and workdays lost. A self-completed questionnaire about the vaccination was sent to 5785 people randomly chosen among 18 249 workers. When any sick leave was incurred amongst the respondents (63.3%), of whom 301 were vaccinated and 3362 unvaccinated, a clinical form was completed by the private physician and the medical adviser of the firm (Electricité de France and Gaz de France). A final self-completed questionnaire was sent to people whose sick leave was not documented by a physician's reported diagnosis. In total, we obtained complete data for 90.9% of the sampling. The vaccine coverage rate of 8.2% [95% confidence interval (95% CI) = 7.4-9.0%] was higher in men than in women, increasing with age and professional category. Among the 775 subjects with a medical diagnosis, the vaccine effectiveness was not significant: 27.3% (95% CI = -13.8 to 53.5%). In the unvaccinated group, 9.6% had days absent from work, versus 7.0% in the vaccinated group; the two populations were comparable in terms of clinical symptoms, smoking habits, exposure to respiratory risk factors and chronic pathology. The average duration of sick leave for ILI was not significantly different between vaccinated (0.5 days) and unvaccinated workers (0.6 days). Despite the large size of the population and the occurrence of an epidemic due to a virus closely related to the vaccine strain (A/Wuhan/359/95), the vaccine did not effectively protect the small vaccine group nor result in an economic benefit, whatever the professional group.     

Factors associated with repeated influenza vaccine uptake among aged care staff in an Australian sample from 2017 to 2019

Background/AimInfluenza vaccination is strongly recommended every year for aged care staff to protect themselves and minimise risk of transmission to residents. This study aimed to determine the factors associated with repeated annual influenza vaccine uptake among Australian aged care staff from 2017 to 2019.MethodsDemographic, medical and vaccination data collected from the staff, who participated in an observational study from nine aged care facilities under a single provider in Sydney Australia, were analysed retrospectively. Based on the pattern of repeated influenza vaccination from 2017 to 2019, three groups were identified: (1) unvaccinated all three years; (2) vaccinated occasionally(once or twice) over three years; and (3)vaccinated all three years. Multinomial logistic regression analysis was performed to better understand the factors associated with the pattern of repeated influenza vaccination.ResultsFrom a total of 138 staff, between 2017 and 2019, 28.9 % (n = 40) never had a vaccination, while 44.2 % (n = 61) had vaccination occasionally and 26.8 % (n = 37) had vaccination all three years. In the multinomial logistic regression model, those who were<40 years old (OR = 0.57, 95 % CI: 0.19–0.90, p < 0.05) and those who were current smokers (OR = 0.20; 95 % CI: 0.03–0.76, p < 0.05) were less likely to have repeated vaccination for all three years compared to the unvaccinated group. Those who were<40 years old (OR = 0.61; 95 % CI: 0.22–0.68, p < 0.05) and those who were born overseas (OR = 0.50; 95 % CI:0.27–0.69, p < 0.05) were more likely to be vaccinated occasionally compared to the unvaccinated group.ConclusionThe significant predictors of repeated vaccine uptake across the three-year study period among aged care staff were age, smoking status and country of birth (Other vs Australia). Targeted interventions towards the younger age group (<40 years old), smokers and those who were born overseas could improve repeated influenza vaccination uptake in the aged care workforce.     

Female students receiving post-secondary education in Greece: the results of a collaborative human papillomavirus knowledge survey

ObjectivesContrary to the optimistic forecasts, existing until 2008 and despite the incorporation of the vaccine into the Greek National Immunization Program, six years later, the percentage of HPV vaccination coverage in Greece remains disappointingly low. The aim of this extended study was to investigate the knowledge, behaviour and attitude of a representative sample of the initial target group; young female students of Greek higher education institutions to Pap cervical screening, biology of HPV infection and principles of HPV vaccination.Study designCross-sectional study.MethodsOne thousand two hundred ten (1210) questionnaires were completed by young female students aged 17–24 years. The survey questionnaire sought data relating to sociodemographic characteristics, health behaviour and knowledge about HPV, as well as vaccination status.Results79.6% of the sample reported at least one annual gynaecologic examination and 92.6% were familiar with the rationale of cervical screening; however only 52.9% had undergone a Pap smear. 69.7% reported adequate knowledge about HPV and 89.3% were aware of the possible course of HPV infection. Despite most (95.9%) were aware of vaccine availability, vaccinated students represented only 33.1%. According to the multivariate analysis, vaccination status was associated with university studies (OR 1.96; 95% CI: 1.19–3.20), parental area of expertise (OR 2.77; 95% CI: 1.18–6.53, OR 2.03; 95% CI: 1.05–3.94), and adequate knowledge of the reasons for which women should undergo regular cervical screening (OR 4.23; 85% CI: 1.55–11.55). Fear of side-effects and equivocal information were the main reasons of non-vaccination (52.2% and 33.1% respectively). Finally, the majority of unvaccinated individuals showed a positive attitude towards prospective HPV vaccination, providing they received well-documented advising.ConclusionsYoung women attending Greek higher education exhibit a good level of knowledge about HPV and its correlation with cervical cancer. These data highlight the need for further sensitization of the general population.     

Prevalence and determinants of influenza vaccination in Australians aged 40 years and over--a national survey

OBJECTIVES: To determine influenza vaccination coverage in 2001 in Australian adults aged > or = 40 years, assess awareness of and attitudes to influenza vaccine, factors associated with vaccination, and estimate uptake of free vaccine provided to those aged > or = 65 years. METHODS: National computer-assisted telephone interview (CATI) survey in October/November 2001. RESULTS: Interviews were completed with 5,266 people aged > or = 65 and 2,415 aged 40-64 years. Thirty per cent of selected households participated. Overall, 67% of respondents believed that the vaccine was somewhat to very effective in preventing influenza. Seventy-eight per cent of those aged > or = 65 years reported influenza vaccination; 89% had received it free. Independent predictors of vaccination were: belief that influenza vaccine is effective in preventing influenza (OR=13.5, 95% CI 10.6-17.2); and the presence of chronic disease (OR=1.6, 95% CI 1.3-2.0). Overall, 24% of those aged 40-64 years were vaccinated; only 34% of those who met any of the criteria for vaccination (medical risk factor, at-risk occupation, or being Aboriginal or Torres Strait Islander) reported vaccination. CONCLUSIONS: Influenza vaccine coverage was high in those aged > or = 65 years, but coverage of those at-risk aged 40-64 years remained suboptimal. Immunisation against influenza was influenced more by beliefs about the vaccine's effectiveness and existing medical risk factors, rather than socio-demographic factors such as gender and income.     

The impact of socioeconomic level on influenza vaccination among Italian adults and elderly: a cross-sectional study

OBJECTIVE: To assess the predictive factors of influenza vaccination among Italian adults, focusing on socioeconomic differences. METHODS: A cross-sectional study was carried out using interview and self-reported data on 102,095 subjects aged 25-89 years from the national survey "health conditions and health care services use" conducted in Italy in 1999-2000. Analyses were stratified by age and multiple logistic regression models were used to estimate odds ratios (OR) of influenza vaccination. RESULTS: Approximately one in six individuals (17.3%) received an influenza vaccine in the previous 12 months. Older age, poor health status and former smoking were all positively associated with influenza vaccination (P-value<0.05). Lower educated individuals and subjects with manual occupations were less likely to be vaccinated than those better off, with an OR ranging from 0.65 (95% CI 0.55, 0.77) to 0.82 (95% CI 0.71, 0.93). Among individuals aged 65-89 there was no apparent influence of both variables on the likelihood of receiving the influenza vaccine. CONCLUSIONS: Socioeconomic inequalities in influenza vaccine uptake were present among the adults but not among the elderly. Because in Italy the National Health Service provides influenza vaccination to the elderly free of charge, it is possible that this policy attenuated the socioeconomic differential.     

Association between COVID-19 vaccination status,time elapsed since the last vaccine dose,morbidity, and absenteeism among healthcare personnel: A prospective,multicenter study

AimWe assessed the impact of COVID-19 vaccination status and time elapsed since the last vaccine dose on morbidity and absenteeism among healthcare personnel (HCP) in the context of a mandatory vaccination policy.MethodsWe followed 7592 HCP from November 15, 2021 through April 17, 2022. Full COVID-19 vaccination was defined as a primary vaccination series plus a booster dose at least six months later.ResultsThere were 6496 (85.6 %) fully vaccinated, 953 (12.5 %) not fully vaccinated, and 143 (1.9 %) unvaccinated HCP. A total of 2182 absenteeism episodes occurred. Of 2088 absenteeism episodes among vaccinated HCP with known vaccination status, 1971 (94.4 %) concerned fully vaccinated and 117 (5.6 %) not fully vaccinated. Fully vaccinated HCP had 1.6 fewer days of absence compared to those not fully vaccinated (8.1 versus 9.7; p-value < 0.001). Multivariable regression analyses showed that full vaccination was associated with shorter absenteeism compared to not full vaccination (OR: 0.56; 95 % CI: 0.36–0.87; p-value = 0.01). Compared to a history of ≤ 17.1 weeks since the last dose, a history of > 17.1 weeks since the last dose was associated with longer absenteeism (OR: 1.22, 95 % CI:1.02–1.46; p-value = 0.026) and increased risk for febrile episode (OR: 1.33; 95 % CI: 1.09–1.63; p-value = 0.004), influenza-like illness (OR: 1.53, 95 % CI: 1.02–2.30; p-value = 0.038), and COVID-19 (OR: 1.72; 95 % CI: 1.24–2.39; p-value = 0.001).ConclusionsThe COVID-19 pandemic continues to impose a considerable impact on HCP. The administration of a vaccine dose in less than four months before significantly protected against COVID-19 and absenteeism duration, irrespective of COVID-19 vaccination status. Defining the optimal timing of boosters is imperative.     

Prevalence and predictors of influenza vaccination among residents of long-term care facilities

Influenza is a respiratory illness which results in significant morbidity and mortality, especially in the older population. Older people living in Long-Term Care Facilities (LTCFs) have a significantly higher risk of infection and complications from influenza. Influenza vaccine is considered the best strategy to prevent infection in high-risk populations. In Australia, the Communicable Diseases Network Australia (CNDA) suggests a vaccination coverage rate of 95% in both staff and residents¹. This study aims to measure the vaccination coverage rates for residents in LTCFs and identify predictors of vaccination uptake for these individuals.This study was conducted in nine LTCFs in four sites from March to September 2018. This was done via medical record reviews for residents over 65 years old in these LTCFs, collecting information such as vaccination status, age, gender, ethnicity and occupation. Simple and multivariable logistic regression was used to calculate the Odds Ratio (OR) to determine significant predictors of influenza vaccination uptake.The overall vaccination rate among LTCF residents was 83.6%. Significant predictors of vaccination were LTCF location, ethnicity and previous year vaccination status. Residents in LTCF Site D were less likely to be vaccinated compared to Site A (OR 0.11, 95% CI 0.02–0.61), non-Caucasians were less likely to get vaccinated (OR 0.09, 95% CI 0.01–0.67), and residents who refused the 2017 vaccine were less likely to be vaccinated (OR 0.04, 95% CI 0.01–0.15).Compared with previous Australian studies on LTCF vaccination rates, the overall vaccination rate was high in these LTCFs (83.6% versus 66–84%), but it varied across different sites. Reasons for varying vaccination rates should be explored further – for example, lower rates in non-Caucasians with diverse cultural backgrounds. Better understanding the causes of under-vaccination can help improve vaccination programs in LTCFs.     

The additive benefits of influenza and pneumococcal vaccinations during influenza seasons among elderly persons with chronic lung disease

Uncertainty regarding the benefits of pneumococcal vaccination may contribute to the under use of this vaccine. The present study was conducted to clarify the benefits of influenza and pneumococcal vaccinations during 3 influenza seasons among elderly persons with chronic lung disease. All elderly members of a large managed care organization with a prior diagnosis of chronic lung disease were included in a cohort that was followed over three influenza seasons (1993–1994, 1994–1995, and 1995–1996). Data obtained from the administrative data bases of the health care organization included baseline demographic and health characteristics, influenza vaccination status for each season, date of pneumococcal vaccination, and outcomes for each season including hospitalization for pneumonia and death. Cox proportional hazards regression and Poisson regression with repeated measures were used to compare the risk of outcomes among vaccinated and unvaccinated persons while controlling for covariates and confounders. During the three influenza seasons, influenza vaccination alone was associated with a 52% reduction (95% CI 18–72) in hospitalizations for pneumonia and a 70% reduction (95% CI 57–89) in death. Pneumococcal vaccination alone during the three influenza seasons was associated with a 27% reduction (95% CI 13–52) in hospitalizations for pneumonia and a 34% reduction (95% CI 6–54) in death. Both vaccinations together demonstrated additive benefits. When both vaccinations had been received, there was a 63% reduction (95% CI 29–80) in hospitalizations for pneumonia and an 81% reduction (95% CI 68–88) in death versus when neither had been received. These findings suggest pneumococcal vaccination is associated with substantial benefits for elderly persons with chronic lung disease.     

Factors associated with Q fever vaccination in Australian wildlife rehabilitators

Australian wildlife rehabilitators (AWR) are at risk of contracting Q fever, a serious zoonotic disease caused by Coxiella burnetii. Despite Australian government recommendations for AWR to receive Q fever vaccination (QFV), and the availability of a safe and effective vaccine in Australia, shortfalls in vaccine uptake have been observed in AWR. This study aimed to determine factors associated with QFV status and describe AWR attitudes and potential barriers towards QFV. Data were obtained from a nationwide, online, cross-sectional survey of AWR undertaken in 2018. Approximately-three quarters (200/265; 75.5 %) of those that had heard of Q fever were also aware of the Q fever vaccine, and of those, 25.5 % (51/200) were vaccinated. Barriers to QFV, among unvaccinated respondents who had also heard of Q fever and the vaccine (149/200; 74.5 %), included concerns regarding the safety, efficacy, and importance of the Q fever vaccine. Complacency toward vaccination, convenience of vaccination, and a lack of Q fever knowledge were also notable barriers. Only 27.7 % (41/148) of respondents reported having had vaccination recommended to them. Multivariable logistic regression identified that vaccinated AWR were more likely to be aged ≤ 50 years (OR 4.51, 95 % CI: 2.14–10.11), have had a university level education (OR 2.78, 95 % CI: 1.39–5.73), have resided in New South Wales/Australian Capital Territory and Queensland than in other Australian jurisdictions (OR 2.9, 95 % CI: 1.10–8.83 and OR 4.82, 95 % CI: 1.64–16.00 respectively) and have attended an animal birth (OR 2.14, 95 % CI: 1.02–4.73). Knowledge gaps regarding Q fever and QFV in AWR demonstrated the need for interventions to raise the awareness of the potential health consequences of C. burnetii exposure and Q fever prevention. Education programs to allow AWR to develop an informed perspective of Q fever and QFV, coupled with improvements in vaccine affordability and the implementation of programs to enhance accessibility, may also increase vaccine uptake.