Measuring the timeliness of childhood vaccinations: Using cohort data and routine health records to evaluate quality of immunisation services

BackgroundTo achieve full benefits of vaccination programmes, high uptake and timely receipt of vaccinations are required.ObjectivesTo examine uptake and timeliness of infant and pre-school booster vaccines using cohort study data linked to health records.MethodsWe included 1782 children, born between 2000 and 2001, participating in the Millennium Cohort Study and resident in Wales, whose parents gave consent for linkage to National Community Child Health Database records at the age seven year contact. We examined age at receipt, timeliness of vaccination (early, on-time, delayed, or never), and intervals between vaccine doses, based on the recommended schedule for children at that time, of the following vaccines: primary (diphtheria, tetanus, pertussis (DTP), polio, Meningococcal C (Men C), Haemophilus influenzae type b (Hib)); first dose of measles, mumps and rubella (MMR); and pre-school childhood vaccinations (DTP, polio, MMR). We compared parental report with child health recorded MMR vaccination status at age three years.ResultsWhile 94% of children received the first dose of primary vaccines early or on time, this was lower for subsequent doses (82%, 65% and 88% for second and third doses and pre-school booster respectively). Median intervals between doses exceeded the recommended schedule for all but the first dose with marked variation between children. There was high concordance (97%) between parental reported and child health recorded MMR status.ConclusionsRoutine immunisation records provide useful information on timely receipt of vaccines and can be used to assess the quality of childhood vaccination programmes. Parental report of MMR vaccine status is reliable.     

Uptake and timeliness of rotavirus vaccination in Norway: The first year post-introduction

BackgroundTo minimise vaccine-associated risk of intussusception following rotavirus vaccination, Norway adopted very strict age limits for initiating and completing the vaccine series at the time rotavirus vaccination was included in the national immunisation programme, October 2014. Although Norway has a high coverage for routine childhood vaccines, these stringent age limits could negatively affect rotavirus coverage. We documented the status and impact of rotavirus vaccination on other infant vaccines during the first year after its introduction.MethodsWe used individual vaccination data from the national immunisation register to calculate coverage for rotavirus and other vaccines and examine adherence with the recommended schedules. We identified factors associated with completing the full rotavirus series by performing multiple logistic regression analyses. We also evaluated potential changes in uptake and timeliness of other routine vaccines after the introduction of rotavirus vaccine using the Kaplan-Meier method.ResultsThe national coverage for rotavirus vaccine achieved a year after the introduction was 89% for one dose and 82% for two doses, respectively. Among fully rotavirus-vaccinated children, 98% received both doses within the upper age limit and 90% received both doses according to the recommended schedule. The child’s age at the initiation of rotavirus series and being vaccinated with diphtheria, tetanus, pertussis, polio and Haemophilus influenzae type b (DTaP/IPV/Hib) and pneumococcal vaccines were the strongest predictors of completing the full rotavirus series. No major changes in uptake and timeliness of other paediatric vaccines were observed after introduction of rotavirus vaccine.ConclusionsNorway achieved a high national coverage and excellent adherence with the strict age limits for rotavirus vaccine administration during the first year of introduction, indicating robustness of the national immunisation programme. Rotavirus vaccination did not impact coverage or timeliness of other infant vaccines.     

Duration of protection against Bordetella pertussis infection elicited by whole-cell and acellular vaccine priming in Polish children and adolescents

BackgroundIn the context of reported resurgence of pertussis in the last decade, researchers hypothesized that acellular (aP) pertussis vaccines elicit a shorter-lived protection compared to whole-cell (wP) pertussis vaccines. However, in the studies seeking to demonstrate this hypothesis, exposure to each vaccine type was not concurrent, and contradictory epidemiologic modeling questioned its validity. The context of pertussis vaccination history in Poland, with both vaccine types used concurrently in comparable proportions, provided an opportunity to investigate this hypothesis. We sought to compare waning of protection by primary series vaccine type by measuring anti-pertussis toxin antibody concentrations as proxy for recent infection.Materials and methodsSerological samples from 2,745 children and adolescents aged ≥5 years and <16 years and with completed 5-dose pertussis vaccination series were tested by ELISA for pertussis toxin (PT) antibodies. Participants were stratified by type of priming vaccine (wP or aP). Vaccination timeliness and priming-specific trends in anti-PT antibody levels by time since last vaccine dose were analyzed.ResultsA total of 1,161 (42.5%) children received wP vaccines, and 1,314 (48.1%) received aP vaccines for their primary series and toddler booster. Overall, 53.57% of the subjects received doses 2–4 in a timely manner, while only 41.52% received all 5 doses at the recommended intervals. Using GMCs or seropositivity measures, both priming groups showed a re-increase in anti-PT antibody levels signing infection in recent years from 8 years after the school-entry booster onward. Comparisons did not show any significant differences between the two groups in the timing or intensity of this re-increase.ConclusionOur results clearly confirm that vaccine-elicited immunity against pertussis wanes among adolescents even after a complete infant, toddler and school-entry vaccination series. The timing and intensity of the waning of protection appear similar with whole-cell as with acellular pertussis vaccines.     

Delivering prenatal pertussis vaccine through maternity services in England: What is the impact on vaccine coverage?

BackgroundPrenatal pertussis vaccination was introduced in 2012 in England and is primarily delivered through general practice. Since 2017 some maternity services are commissioned to offer it too. We aimed to describe the maternity service delivery of prenatal pertussis vaccination and its impact on vaccine uptake.MethodsWe described the proportion of maternity services in England commissioned to offer pertussis vaccination to pregnant women in 2017/18 and the proportion of women vaccinated in this setting using a self-administered survey of NHS commissioners. We categorised clinical commissioning groups (CCGs) in England into “implementing” and “non-implementing” pertussis vaccination in maternity services. We identified CCGs where vaccination data was reliably transferred from maternity services to primary care records (source of routine data on vaccine uptake) and among those compared changes in vaccine uptake in implementing vs non-implementing CCGs between March 2016 (before implementation) and March 2018 (after).FindingsOf 141 maternity service units in England, 61% delivered prenatal pertussis vaccine in 2017/18. Of those 57.0% of maternity services immunized less than 10% of pregnant women and only 7.1% of maternity services immunized more than 40% of pregnant women. Between March 2016 and March 2018, coverage increased by 19.6% among non-implementing CCGs compared with 17.8% among all implementing CCGs (difference −2.2, p = 0.48) and 28.2% among implementing CCGs with reliable methods of data transfer (difference 8.6, p = 0.04). This difference translated to a difference of 1.6 percentage points in absolute terms.InterpretationDelivering pertussis vaccine through maternity services has a moderate but important impact on vaccine uptake. There is a need to improve data transfer on vaccines administered in maternity service units to primary care. Maternity services should offer the vaccine to improve coverage and thus optimise protection for young infants. Barriers to effective programme implementation should be investigated and addressed.     

Inequalities in childhood vaccination timing and completion in London

The UK primary vaccination course includes vaccination against diphtheria, tetanus, pertussis, polio and Haemophilus influenzae type b (DTaP/IPV/Hib) and is scheduled at ages four, 8 and 12 weeks, followed by a ‘preschool booster’ at age three years four months. Vaccine coverage is generally measured at age one, two and five years. In addition to high coverage, vaccination should be timely to maximise population protection.Vaccination histories for 315,381 children born March 2001 to April 2010 were extracted from Child Health Information Systems in nine London health service areas and grouped into first and fifth birthday cohorts. We assessed timeliness of receipt of DTaP/IPV/Hib and drop-out rates by ethnicity, deprivation and area.Most children received their first, second and third doses on time at two, three, and four months. Among children completing by one year and after adjusting for deprivation and health area, compared with White-British children, Somali and Bangladeshi children were less likely to have received three doses of DTaP/IPV/Hib by six months of age (−11% and −5% respectively). Differences in timeliness by deprivation and health area existed, but were smaller. Compared with White-British children, children of Polish, Somali and Caribbean ethnicities were less likely to return for preschool booster, with a drop-out rate at least 7% higher in these groups. Within the fifth birthday cohort, only 2.3% of children who were completely unvaccinated (575/25,095) at age one year were fully vaccinated by age five. Higher proportions of partially vaccinated (one or two doses) children at age one year went on to be fully vaccinated by age five ((836/3213) 26.0% and (3565/6076) 58.7% respectively).These inequalities suggest that tailored approaches may be required to target specific groups with regards to improving vaccine uptake.     

Differences of humoral and cellular immune response to an acellular pertussis booster in adolescents with a whole cell or acellular primary vaccination

To study the pertussis-specific immune response of adolescents with different prevaccination schedules, we measured the humoral and cell-mediated immunity (CMI) to pertussis antigens before and after a five-component Tdap booster vaccination in 78 adolescents, who had previously received either five doses of a two-component acellular pertussis vaccine (aP; last dose age 4-6 years), four doses of aP (last dose age 18-24 months), or four doses of whole cell pertussis vaccine (wcP; last dose age 18-24 months). The proportion of participants with a twofold rise in titre was 79% against pertussis toxin (PT), 94% against filamentous hemagglutinin (FHA), and 99% against pertactin (PRN) without significant differences between the three groups. However, participants with primary wcP vaccination showed higher postvaccination titres to pertussis toxin (geometric mean titre, GMT 50.3EU/ml) than those with either four (GMT 17.1EU/ml) or five (GMT 16.4EU/ml) previous aP doses. CMI indices to PT, FHA, PRN and fimbriae (FIM) increased after vaccination and were similar between groups. The current adolescent Tdap booster immunization induced good humoral and cellular immune response to pertussis. The higher antibody titres to pertussis toxin may indicate a more effective priming of B cell memory after primary whole-cell vaccination.     

Age-specific effectiveness following each dose of acellular pertussis vaccine among infants and children in New Zealand

BackgroundThough it is believed the switch from whole cell to acellular pertussis vaccine has contributed to the resurgence of pertussis disease, few studies have evaluated vaccine effectiveness (VE) and duration of protection provided by an acellular vaccine schedule including three primary doses but no toddler-age dose. We assessed this schedule in New Zealand (NZ), a setting with historically high rates of pertussis disease, and low but recently improved immunisation coverage. We further evaluated protection following the preschool-age booster dose.MethodsWe performed a nested case-control study using national-level healthcare data. Hospitalised and non-hospitalised pertussis was detected among children 6 weeks to 7 years of age between January 2006 and December 2013. The NZ National Immunisation Register provided vaccination status for cases and controls. Conditional logistic regression was used to calculate dose-specific VE with duration of immunity examined by stratifying VE into ages aligned with the immunisation schedule.ResultsVE against pertussis hospitalisation was 93% (95% confidence interval [CI]: 87, 96) following three doses among infants aged 5–11 months who received three compared to zero doses. This protection was sustained through children’s fourth birthdays (VE ⩾ 91%). VE against non-hospitalised pertussis was also sustained after three doses, from 86% (95% CI: 80, 90) among 5–11 month olds to 84% (95% CI: 80, 88) among 3-year-olds. Following the first booster dose at 4 years of age, the protective VE of 93% (95% CI: 90, 95) among 4-year-olds continued through 7 years of age (VE ⩾ 91%).ConclusionsWe found a high level of protection with no reduction in VE following both the primary course and the first booster dose. These findings support a 3-dose primary course of acellular vaccine with no booster dose until 4 years of age.     

Vaccine timeliness and prevalence of undervaccination patterns in children ages 0–19 months,U.S., National Immunization Survey-Child 2017

ObjectivesTypically, early childhood vaccination coverage in the U.S. is measured as the proportion of children by age 24 months who completed recommended vaccine series. However, these measures do not reflect whether vaccine doses were received at the ages recommended by the U.S. Advisory Committee on Immunization Practices, or whether children received vaccines concomitantly, per the ACIP recommended schedule. This study’s objective was to quantify vaccine timeliness and prevalence of specific patterns of undervaccination in U.S. children ages 0–19 months.MethodsUsing 2017 National Immunization Survey-Child data, we calculated days undervaccinated for the combined 7-vaccine series and distinguished undervaccination patterns indicative of parental vaccine hesitancy, such as spreading out vaccines across visits (“shot-limiting”) or starting some but not all recommended vaccine series (“selective vaccination”), from other non-hesitancy patterns, such as missing final vaccine doses or receiving all doses, with some or all late. We measured associations between demographic, socioeconomic and other characteristics with undervaccination patterns using multivariable log-linked binomial regression. Analyses accounted for the complex survey design.ResultsAmong n = 15,333 U.S. children, only 41.2% received all recommended vaccine doses on-time by age 19 months. Approximately 20.9% of children had an undervaccination pattern suggestive of parental vaccine hesitancy, and 36.2% had other undervaccination non-hesitancy patterns. Uninsured children and those with lower levels of maternal education were more likely to exhibit undervaccination patterns suggestive of parental hesitancy. Lower levels of maternal education were also associated with other non-hesitancy undervaccination patterns.ConclusionsMore than half of children in the U.S. are undervaccinated at some point by 19 months of age. Ongoing assessment of vaccine timeliness and immunization schedule adherence could facilitate timely and targeted public health interventions in populations with high levels of undervaccination.     

Pertussis vaccination during pregnancy: Antibody persistence in infants

Maternal pertussis vaccination is associated with higher levels of pertussis antibodies at birth. We assessed the persistence of pertussis antibodies until primary vaccination in infants whose mothers received Tdap (tetanus, diphtheria, acellular pertussis) vaccine during pregnancy. Infants were born at the Hospital Clinic of Barcelona (Spain) in November 2014. Anti-PT IgG was determined by ELISA at delivery, between the first and second month of life, and estimated at 2 months of age. The study included 37 infants whose mothers received Tdap between 21 and 38 weeks of gestation. Infants presented a decline in GMC of anti-PT IgG between peripartum and follow-up levels, 52.7 (95% CI 34.7–80.2) versus 7.5 (95% CI 4.2–13.3) at 2 months of age (p < 0.001). The median half-life of maternal antibodies was 47 days. More than half (51.4%) the infants presented detectable anti-PT IgG before the start of primary infant vaccination.     

Pertussis vaccination during pregnancy in Vietnam: Results of a randomized controlled trial Pertussis vaccination during pregnancy

A pertussis vaccination during pregnancy has recently been adopted in several countries to indirectly protect young infants. This study assessed the effect of adding a pertussis component to the tetanus vaccination, in the pregnancy immunization program in Vietnam.A randomized controlled trial was performed. Pregnant women received either a Tdap (tetanus, diphtheria acellular pertussis) vaccine or a tetanus only vaccine between 19 and 35 weeks’ gestational age. Immunoglobulin G (IgG) against tetanus (TT), diphtheria (DT), pertussis toxin (PT), filamentous hemaglutinin (FHA) and pertactin (Prn) were measured using commercial ELISA tests, at baseline, 1 month after maternal vaccination, at delivery, and in infants from cord blood and before and after the primary series (EPI: month 2-3-4) of a pertussis containing vaccine.Significantly higher geometric mean concentrations (GMC) were observed for all 3 measured pertussis antigens in the offspring of the Tdap group, up to 2 months of age. One month after completion of the primary infant vaccination schedule, anti-Prn GMC, but not anti-PT and anti-FHA GMCs, was significantly (p = 0.006) higher in the control group.Maternal antibodies induced by vaccination during pregnancy close the susceptibility gap for pertussis in young infants. Limited interference with the infant vaccine responses was observed. Whether this interference effect disappears with the administration of a fourth vaccine dose is further studied.     

Effectiveness of maternal pertussis vaccination in Singapore: A test-negative case-control study

Pertussis vaccination (Tdap -Tetanus-diphtheria-acellular pertussis) for pregnant women has been recommended since November 2017 in Singapore. In this prospective test-negative case-control study from 2018 to 2019, we aimed to evaluate vaccine effectiveness (VE) against pertussis infection and pertussis-related intensive care unit (ICU) admission according to Tdap (Tetanus-diphtheria-acellular pertussis) during pregnancy and/or infant pertussis vaccination. A total of 58 children (26 cases, 32 controls) were recruited with 4 ICU admissions. The median age was 3 months (interquartile range [IQR] 1.50–4.56 months). Overall, 25.9 % of mothers had received antenatal Tdap vaccination and 43.1 % of infants received pertussis vaccination, majority only 1 dose. Tdap in pregnancy alone without infant vaccine or with 0–1 infant dose had a VE of 97.62 % (95 % confidence interval [CI] 53.25–99.88 %), 98.17 % (95 %CI 66.61–99.9 %) respectively, against pertussis infection and 71.9 % (95 %CI 0.0–98.64), 75.86 % (95 % CI 0.0–98.78) respectively, against ICU admissions. Conclusion: Maternal Tdap vaccination was highly protective against infant pertussis and should be routinely recommended for all pregnant women.     

Choice of measures of vaccination and estimates of risk of pediatric pertussis

BackgroundVaccination uptake at the individual level can be assessed in a variety of ways, including traditional measures of being up-to-date (UTD), measures of UTD that consider dose timing, like age-appropriate vaccination, and risk reduction from individual doses. This analysis compared methods of operationalizing vaccination uptake and corresponding risk of pertussis infection.MethodsCity-wide case-control study of children in Philadelphia aged 3 months through 6 years, between 2001 and 2013. Multiple logistic regression was used to isolate the independent effects of each measure of vaccination uptake and the corresponding relative odds of pertussis.ResultsBeing UTD on vaccinations was associated with a 52% reduction in risk of pertussis (OR 0.48, 95% CI: 0.34, 0.69). Evaluation of delayed receipt of vaccine versus on-time UTD yielded similar results. There was a decrease in risk of pertussis for each additional dose received with the greatest reduction in pertussis infection observed from the first (OR 0.48, 95% CI: 0.28, 0.83) and second dose (OR 0.17, 95% CI: 0.08, 0.34). Additional doses conferred minimal additional protection in this age group.ConclusionExamining vaccination status by individual doses may offer improved predictive capacity for identifying children at risk for pertussis infection compared to the traditional UTD measure.     

Determinants of influenza and pertussis vaccine uptake in pregnant women in Ireland: A cross-sectional survey in 2017/18 influenza season

In Ireland seasonal influenza and pertussis vaccination during pregnancy is recommended and every year national campaigns are organised to raise awareness and improve uptake. We estimated influenza and pertussis vaccine uptake and identified factors associated with vaccination status in pregnant women in 2017/18.We conducted a face-to-face omnibus survey, with quota sampling, among women aged 18–55 years and collected socio-demographic characteristics, self-reported vaccination status, awareness of vaccine campaigns, and attitudes towards vaccination. Sample was weighted to ensure representativeness with the target population. We performed univariate and multivariable logistic regression analyses on survey data.Overall, 241 pregnant women were enrolled. Influenza and pertussis vaccine uptake was 61.7% and 49.9%, respectively. Awareness of vaccine campaign and socio-economic status (SES) were associated with both influenza and pertussis vaccine uptake. The association between SES and uptake of vaccines differed by awareness. Women aware of the influenza vaccine campaign and with mid and low SES were less likely to be vaccinated, compared to those with high SES (aOR = 0.46; 95%CI: 0.22–0.97; aOR = 0.27; 95%CI: 0.12–0.60, respectively); women not aware of the pertussis vaccine campaign and with mid and low SES were less likely to be vaccinated, compared to those aware and with high SES (aOR = 0.15; 95%CI: 0.04–0.48; aOR = 0.05; 95%CI: 0.01–0.24, respectively).General practitioner (GP) recommendation was the main reason for receiving influenza vaccine (39.2%), and 71.8% of women were recommended pertussis vaccination from their GPs.The survey reports moderate uptake of vaccines among pregnant women, inequalities in uptake by SES and identifies GPs as primary source for vaccine recommendation. We recommend multifaceted campaigns, by engaging GPs, to target all socio-economic groups.     

Beyond coverage: Rural-urban disparities in the timeliness of childhood vaccinations in Tanzania

BackgroundTimely vaccination maximizes efficacy for preventing infectious diseases. In the absence of national vaccination registries, representative sample survey data hold vital information on vaccination coverage and timeliness. This study characterizes vaccination coverage and timeliness in Tanzania and provides an analytic template to inform contextually relevant interventions and evaluate immunization programs.MethodsCross-sectional data on 6,092 children under age 3 from the 2015–16 Tanzania Demographic and Health Survey were used to examine coverage and timeliness for 14 vaccine doses recommended in the first year of life. The Kaplan-Meier method was used to model time to vaccination. Cox proportional hazard models were used to examine factors associated with timely vaccination.ResultsSubstantial rural–urban disparities in vaccination coverage and timeliness were observed for all vaccines. Across 14 recommended doses, documented coverage ranged from 52 % to 79 %. Median vaccination delays lasted up to 35 days; gaps were larger among rural than urban children and for later doses in vaccine series. Among rural children, median delays exceeded 35 days for the 3^rd doses of the polio, pentavalent, and pneumococcal vaccines. Median delays among urban children were < 21 days for all doses. Among rural and urban children, lower maternal education and delivery at home were associated with increased risk of delayed vaccination. In rural settings, less household wealth and greater distance to a health facility were also associated with increased risk of delayed vaccination.DiscussionThis study highlights persistent gaps in uptake and timeliness of childhood vaccinations in Tanzania and substantial rural–urban disparities. While the results provide an informative situation assessment and outline strategies for identifying unvaccinated children, a national electronic registry is critical for comprehensive assessments of the performance of vaccination programs. The timeliness measure employed in this study—the amount of time children are un- or undervaccinated—may serve as a sensitive performance metric for these programs.     

A multisite study of pertussis vaccine effectiveness by time since last vaccine dose from three Canadian provinces: A Canadian Immunization Research Network study

BackgroundPertussis remains poorly controlled relative to other diseases targeted by childhood vaccination programs. We combined estimates from four population-based studies of pertussis vaccine effectiveness (VE) in three Canadian provinces using a meta-analytic approach to improve precision and explore regional variation in VE and durability of protection.MethodsStudies were conducted in Alberta, Manitoba, and Ontario over periods ranging from 1996 to 2015. Adjusted log odds ratios (OR; VE = 100*[1-OR]) of the effect of vaccination on pertussis risk were estimated by time since last vaccination in each study and pooled using DerSimonian and Laird random-effects models. We used the I² statistic to estimate between-study heterogeneity and assessed methodological and clinical heterogeneity through subgroup analyses of study design and age.ResultsData on 3,270 pertussis cases and 23,863 controls were available. Pertussis VE declined from 86% (95% CI 79%-90%, I² = 81.5%) at < 1 year since last vaccination to 51% (11%-74%, I² = 80.9%) by ≥ 8 years. Effect estimates were the most heterogeneous in the least and most elapsed time periods since last vaccine dose. This was attributable mostly to variation between provinces in the distribution of age groups and number of vaccine doses received within time periods, as well as study design and small numbers in the most elapsed time period.Interpretation: Consistent trends of decreasing pertussis VE with increasing time since last vaccination across three Canadian provinces indicate the need for immunization schedules and vaccine development to optimize protection for all individuals, especially for adolescents and young adults at greatest risk of infection.     

Impact of maternally derived pertussis antibody titers on infant whole-cell pertussis vaccine response in a low income setting

BackgroundMaternal vaccines against pertussis are not yet recommended in the developing world. Besides unclear burden estimates, another concern is that transplacental transfer of maternal pertussis antibodies could result in attenuation of the immune response to whole cell pertussis (DTwP) primary vaccination series in infants. This study was taken up to determine whether higher levels of maternal pertussis antibodies attenuate immune response of infants to DTwP vaccination series given at 6–10–14 weeks of age.MethodologyA total of 261 pregnant women and their infants from four low-income settlements in Karachi, Pakistan were enrolled in this study. The study endpoints were infant antibody titers for Pertussis toxin (PTx), Filamentous hemagglutinin antigen (FHA), Pertactin (PRN) and Fimbriae type 2/3 (FIM) – from birth through 18 weeks of age. Cord blood or pre-vaccine pertussis antibody titers indicate the concentration of maternal antibodies transferred to infants. Linear regression models were used to determine the association between higher maternal antibody titers and infant immune response to DTwP vaccine. Geometric Mean Ratio (GMR) was calculated as the ratio of infant antibody titers at specified time points against the maternal antibody titers at the time of delivery.ResultsAt eighteen weeks of age, the adjusted β regression coefficient for PTx was 0.06 (95% CI: -0.49-0.61), FHA 0.02 (95% CI: -0.26 -0.29), PRN 0.02 (95%CI -0.38- 0.43), and FIM 0.17 (95%CI: -0.21-0.54). Among infants who received at least two doses of DTwP vaccine, higher maternal antibody titers did not have any attenuating effect on infant post-immunization antibody titers against all four pertussis antigens.ConclusionMaternal pertussis antibodies did not attenuate infant’s immune response to pertussis antigens in DTwP primary vaccine given at 6–10–14 weeks of age.     

Vaccine decision-making begins in pregnancy: Correlation between vaccine concerns,intentions and maternal vaccination with subsequent childhood vaccine uptake

IntroductionMaternal and childhood vaccine decision-making begins prenatally. Amongst pregnant Australian women we aimed to ascertain vaccine information received, maternal immunisation uptake and attitudes and concerns regarding childhood vaccination. We also aimed to determine any correlation between a) intentions and concerns regarding childhood vaccination, (b) concerns about pregnancy vaccination, (c) socioeconomic status (SES) and (d) uptake of influenza and pertussis vaccines during pregnancy and routine vaccines during childhood.MethodsWomen attending public antenatal clinics were recruited in three Australian states. Surveys were completed on iPads. Follow-up phone surveys were done three to six months post delivery, and infant vaccination status obtained via the Australian Childhood Immunisation Register (ACIR).ResultsBetween October 2015 and March 2016, 975 (82%) of 1184 mothers consented and 406 (42%) agreed to a follow up survey, post delivery. First-time mothers (445; 49%) had significantly more vaccine concerns in pregnancy and only 73% had made a decision about childhood vaccination compared to 89% of mothers with existing children (p-value < 0.001). 66% of mothers reported receiving enough information during pregnancy on childhood vaccination. In the post delivery survey, 46% and 82% of mothers reported receiving pregnancy influenza and pertussis vaccines respectively. The mother's degree of vaccine hesitancy and two attitudinal factors were correlated with vaccine uptake post delivery. There was no association between reported maternal vaccine uptake or SES and childhood vaccine uptake.ConclusionFirst time mothers are more vaccine hesitant and undecided about childhood vaccination, and only two thirds of all mothers believed they received enough information during pregnancy. New interventions to improve both education and communication on childhood and maternal vaccines, delivered by midwives and obstetricians in the Australian public hospital system, may reduce vaccine hesitancy for all mothers in pregnancy and post delivery, particularly first-time mothers.     

Pertussis vaccination in infancy lowers the incidence of pertussis disease and the rate of hospitalisation after one and two doses: analyses of 10 years of pertussis surveillance

Objectives

Shortly after pertussis vaccination was reintroduced in Sweden in 1996, an intensified pertussis disease surveillance programme was set up. In this study, we report on in-depth analyses of age–dose–number-specific incidences and the rate of pertussis hospitalisation for children with no, 1 or 2 doses of an acellular pertussis vaccine before pertussis disease. Vaccine coverage, the timeliness of childhood vaccination and the effect of later than scheduled pertussis vaccination(s) are also examined.

Study design

Children with notified laboratory-confirmed (culture or PCR) pertussis disease were evaluated among the surveillance population of about 1 million infants, born between 1996 and 2007 and followed for pertussis disease from October 1997 to December 2007, for nearly 6 million person-years. Birth and vaccination dates of the diseased children are known from the surveillance programme. To estimate denominators of the age–dose–number-specific pertussis incidences, we used birth and vaccination dates from a vaccine trial with more than 72,000 infants combined with national pertussis vaccine coverage data for children in the surveillance population.

Results

For infants from 3 to <5 months of age, the incidence of pertussis disease with at least 14 days of cough decreased from 264/100,000 for unvaccinated infants to 155/100,000 for infants with one dose of a pertussis vaccine prior to onset of the disease. In the age range 5 to <12 months, the age–dose specific incidences were 526, 95, and 24/100,000 for infants with no, 1 and 2 doses, respectively. The rate of hospitalisation for infants with 1 dose of a pertussis vaccine prior to onset of the disease was significantly lower than for unvaccinated infants of the same age.For many infants, there is a delay in administration of the vaccine doses according to the regular 3–5–12 month schedule (which has been the case for many years). Hypothetically, if all infants had been vaccinated exactly on schedule, we would expect about 28% fewer pertussis cases with at least 14 days of cough and 38% fewer hospitalisations due to pertussis, of cases possible to influence by vaccinations on schedule.

Conclusion

Pertussis vaccination had a significant effect among infants already after the first dose. This is particularly important for premature infants and infants with severe respiratory and cardiac diseases. A moderate decrease in the incidence of pertussis disease in infants and rate of hospitalisation could be expected if primary vaccinations were carried out closer to the scheduled time than is currently the practice in Sweden.     

Flu and pertussis vaccination during pregnancy in Geneva during the COVID-19 pandemic: A multicentric,prospective, survey-based study

ObjectiveTo determine pertussis and influenza vaccination coverage during pregnancy among women delivering in all the maternities of Geneva (Switzerland), during the COVID-19 pandemic.MethodsAll women delivering in all the maternity centres of the canton of Geneva from 1st November 2020 to 30th November 2020 (beginning of the flu vaccination season) and from 8th March 2021 to 7th April 2021 (end of the flu vaccination season) had their records checked upon admission to the labour ward regarding pertussis and influenza vaccination during pregnancy. Reasons for non-vaccination were recorded. Univariate and multivariate analyses were done to identify predictors of vaccine uptake.Results951 women delivered in Geneva during the two study periods, of which 950 were included in the study. 86.2% were vaccinated against pertussis, with no significant difference between the study periods (87.5% vs 85% at the beginning and end of the flu vaccination season respectively). 49.8% were vaccinated against influenza, with no significant difference between the study periods (48.8% vs 50.7% beginning and end of the flu vaccination season respectively). The influenza vaccine was 5 times more likely not to be proposed (8.9% vs. 1.7%) and 3 times more likely to be refused (26.6% vs. 8%) than the pertussis vaccine. Main reason for refusal was a lack of maternal desire for both vaccines, but not vaccine fear. Maternal parity ≥ 1 was significantly associated with pertussis vaccine uptake at univariate analysis. Women were significantly more likely to accept the influenza vaccine if they had a university degree or if they did not deliver in a midwife-only run delivery unit in both univariate and multivariate analysis.ConclusionsIn Geneva, most gynaecologists offer pertussis immunization during antenatal care and uptake is high, but more efforts must be done to increase influenza vaccination coverage. Education level impacts maternal flu vaccination uptake, but other social disparities did not.