Prenatal maternal COVID-19 vaccination and pregnancy outcomes

BackgroundPrenatal maternal physiological changes may cause severe COVID-19 among pregnant women. The Pfizer-BioNTech COVID-19 vaccine (BNT162b2 mRNA) has been shown to be highly effective and it is recommended for individuals aged ≥16 years, including pregnant women, although the vaccine has not been tested on the latter.ObjectiveTo study the association between prenatal Pfizer-BioNTech COVID-19 vaccination, pregnancy course and outcomes.Study designA retrospective cohort study was performed, including all women who delivered between January and June 2021 at Soroka University Medical Center, the largest birth center in Israel. Excluded were women diagnosed with COVID-19 in the past, multiple gestations or unknown vaccination status. Pregnancy, delivery and newborn complications were compared between women who received 1 or 2-dose vaccines during pregnancy and unvaccinated women. Multivariable models were used to adjust for background characteristics.ResultsA total of 4,399 women participated in this study, 913 (20.8%) of which were vaccinated during pregnancy. All vaccinations occurred during second or third trimesters. As compared to the unvaccinated women, vaccinated women were older, more likely to conceive following fertility treatments, to have sufficient prenatal care, and of higher socioeconomic position. In both crude and multivariable analyses, no differences were found between the groups in pregnancy, delivery and newborn complications, including gestational age at delivery, incidence of small for gestational age and newborn respiratory complications.ConclusionsPrenatal maternal COVID-19 vaccine has no adverse effects on pregnancy course and outcomes. These findings may help pregnant women and health care providers to make informed decision regarding vaccination.     

The impact of the COVID-19 pandemic on vaccine coverage in Kilifi,Kenya: A retrospective cohort study

The COVID-19 pandemic caused unprecedented disruption in health service delivery, globally. This study sought to provide evidence on the impact of the pandemic on vaccine coverage in Kilifi County, Kenya. We conducted a vaccine coverage survey between April and June 2021 within the Kilifi Health and Demographic Surveillance System (KHDSS). Simple random sampling was used to identify 1500 children aged 6 weeks–59 months. Participants were grouped into three retrospective cohorts based on when they became age-eligible for vaccination: before the pandemic, during the first year, or during the second year of the pandemic. Survival analysis with Cox regression was used to evaluate the association between the time-period at which participants became age-eligible for vaccination and the rate of vaccination within a month of age-eligibility for the third dose of pentavalent vaccine (Pentavalent-3) and within three months of age-eligibility for the first dose of Measles vaccine (MCV-1). A total of 1,341 participants were included in the survey. Compared to the pre-COVID-19 baseline period, the rate of vaccination within a month of age-eligibility for Pentavalent-3 was not significantly different in the first year of the pandemic (adjusted hazard ratio [aHR] 1.03, 95 % confidence interval [CI] 0.90–1.18) and was significantly higher during the second year of the pandemic (aHR 1.33, 95 % CI 1.07–1.65). The rate of vaccination with MCV-1 within three months of age-eligibility was not significantly different among those age-eligible for vaccination during the first year of the pandemic (aHR 1.04, 95 % CI 0.88–1.21) and was 35 % higher during the second year of the pandemic (95 % CI 1.11–1.64), compared to those age-eligible pre-COVID-19. After adjusting for known determinants of vaccination, the COVID-19 pandemic did not adversely affect the rate of vaccination within the KHDSS.     

Worldwide routine immunisation coverage regressed during the first year of the COVID-19 pandemic

Whilst COVID-19 vaccination strategies continue to receive considerable emphasis worldwide, the extent to which routine immunisation (RI) has been impacted during the first year of the pandemic remains unclear. Understanding the existence, extent, and variations in RI disruptions globally may help inform policy and resource prioritisation as the pandemic continues.We modelled historical, country-specific RI trends using publicly available vaccination coverage data for diphtheria, tetanus and pertussis-containing vaccine first-dose (DTP1) and third-dose (DTP3) from 2000 to 2019.We report a 2·9% (95 %_CI: [2·2%; 3·6%]) global decline in DTP3 coverage from an expected 89·2% to a reported 86·3%; and a 2·2% decline in DTP1 coverage (95 %_CI: [1·6%; 2·8%]). These declines translate to levels of coverage last observed in 2005, thus suggesting a potential 15-years setback in RI improvements. Further research is required to understand which factors – e.g., health seeking behaviours or non-pharmaceutical interventions – linked to the COVID-19 crisis impacted vaccination coverage.     

Short term impact of the COVID-19 pandemic on incidence of vaccine preventable diseases and participation in routine infant vaccinations in the Netherlands in the period March-September 2020

We aimed to assess the impact of the COVID-19 pandemic on the incidence of vaccine-preventable diseases (VPDs) and participation in the routine infant vaccination programme in the Netherlands. The incidence of various VPDs initially decreased by 75–97% after the implementation of the Dutch COVID-19 response measures. The participation in the first measles-mumps-rubella vaccination among children scheduled for vaccination in March-September 2020 initially dropped by 6–14% compared with the previous year. After catch-up vaccination, a difference in MMR1 participation of ?1% to ?2% still remained. Thus, the pandemic has reduced the incidence of several VPDs and has had a limited impact on the routine infant vaccination programme.     

Estimating global changes in routine childhood vaccination coverage during the COVID-19 pandemic, 2020–2021

ObjectivesThe COVID-19 pandemic has disrupted the distribution of routine immunizations globally. Multi-country studies assessing a wide spectrum of vaccines and their coverage rates are needed to determine global performance in achieving vaccination goals.MethodsGlobal vaccine coverage data for 16 antigens were obtained from WHO/UNICEF Estimates of National Immunization Coverage. Tobit regression was performed for all country-antigen pairs for which data were continuously available between 2015–2020 or 2015–2021 to predict vaccine coverage in 2020/2021. Vaccines for which multi-dose data were available were assessed to determine whether vaccine coverage for subsequent doses were lower than that of first doses.ResultsVaccine coverage was significantly lower-than-predicted for 13/16 antigens in 2020 and all assessed antigens in 2021. Lower-than-predicted vaccine coverage was typically observed in South America, Africa, Eastern Europe, and Southeast Asia. There was a statistically significant coverage drop for subsequent doses of the diphtheria-tetanus-pertussis, pneumococcus, and rotavirus vaccines compared to first doses in 2020 and 2021.ConclusionThe COVID-19 pandemic exerted larger disruptions to routine vaccination services in 2021 than in 2020. Global efforts will be needed to recoup vaccine coverage losses sustained during the pandemic and broaden vaccine access in areas where coverage was previously inadequate.     

全球新冠疫苗研发与接种策略进展

WHO于2023年5月5日宣布新型冠状病毒感染(corona virus disease 2019,COVID-19)疫情不再构成国际关注的突发公共卫生事件。全球疫情相对稳定,但是各国仍不能放松对COVID-19的警惕。接种新冠疫苗仍是有效的预防手段。本文主要围绕当前全球新冠疫苗研发进展、不同国家疫苗接种策略调整情况等进行对比分析,并结合WHO推荐对新冠疫苗接种策略的最新指导意见,分析探讨全球新冠疫苗研发及各国疫苗接种策略对我国的启示,提出适合我国国情的针对性疫苗接种建议。     

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.     

Potential impact of COVID-19 pandemic on vaccination coverage in children: A case study of measles-containing vaccine administration in the United States (US)

BackgroundThe COVID-19 pandemic and stay-at-home orders have caused an unprecedented decrease in the administration of routinely recommended vaccines. However, the impact of this decrease on overall vaccination coverage in a specific birth cohort is not known.MethodsWe projected measles vaccination coverage for the cohort of children becoming one year old in 2020 in the United States, for different durations of stay-at-home orders, along with varying catch-up vaccination efforts.ResultsA 15% sustained catch-up rate outside stay-at-home orders (compared to what would be expected via natality information) may be necessary to achieve projected vaccination coverage similar to previous years. Permanent decreases in vaccine administration could lead to projected vaccination coverage levels below 80%.ConclusionModeling measles vaccination coverage under a range of scenarios provides useful information about the potential magnitude and impact of under-immunization. Sustained catch-up efforts are needed to assure that measles vaccination coverage remains high.     

Modelling optimal vaccination strategies against COVID-19 in a context of Gamma variant predominance in Brazil

IntroductionBrazil experienced moments of collapse in its health system throughout 2021, driven by the emergence of variants of concern (VOC) combined with an inefficient initial vaccination strategy against Covid-19.ObjectivesTo support decision-makers in formulating COVID-19 immunization policy in the context of limited vaccine availability and evolving variants over time, we evaluate optimal strategies for Covid-19 vaccination in Brazil in 2021, when vaccination was rolled out during Gamma variant predominance.MethodsUsing a discrete-time epidemic model we estimate Covid-19 deaths averted, considering the currently Covid-19 vaccine products and doses available in Brazil; vaccine coverage by target population; and vaccine effectiveness estimates. We evaluated a 5-month time horizon, from early August to the end of December 2021. Optimal vaccination strategies compared the outcomes in terms of averted deaths when varying dose intervals from 8 to 12 weeks, and choosing the minimum coverage levels per age group required prior to expanding vaccination to younger target populations. We also estimated dose availability required over time to allow the implementation of optimal strategies.ResultsTo maximize the number of averted deaths, vaccine coverage of at least 80 % should be reached in older age groups before starting vaccination into subsequent younger age groups. When evaluating varying dose intervals for AZD1222, reducing the dose interval from 12 to 8 weeks for the primary schedule would result in fewer COVID-19 deaths, but this can only be implemented if accompanied by an increase in vaccine supply of at least 50 % over the coming six-months in Brazil.ConclusionCovid-19 immunization strategies should be tailored to local vaccine product availability and supply over time, circulating variants of concern, and vaccine coverage in target population groups. Modelling can provide valuable and timely evidence to support the implementation of vaccination strategies considering the local context, yet following international and regional technical evidence-based guidance.     

COVID-19 vaccination and menstrual cycle characteristics: A prospective cohort study

We prospectively examined the association between COVID-19 vaccination and menstrual cycle characteristics in an internet-based prospective cohort study. We included a sample of 1,137 participants who enrolled in Pregnancy Study Online (PRESTO), a preconception cohort study of couples trying to conceive, during January 2021-August 2022. Eligible participants were aged 21–45 years, United States or Canadian residents, and trying to conceive without fertility treatment. At baseline and every 8 weeks for up to 12 months, participants completed questionnaires on which they provided information on COVID-19 vaccination and menstrual cycle characteristics, including cycle regularity, cycle length, bleed length, heaviness of bleed, and menstrual pain. We fit generalized estimating equation (GEE) models with a log link function and Poisson distribution to estimate the adjusted risk ratio (RR) for irregular cycles associated with COVID-19 vaccination. We used linear regression with GEE to estimate adjusted mean differences in menstrual cycle length associated with COVID-19 vaccination. We adjusted for sociodemographic, lifestyle, medical and reproductive factors. Participants had 1.1 day longer menstrual cycles after receiving the first dose of COVID-19 vaccine (95 % CI: 0.4, 1.9) and 1.3 day longer cycles after receiving the second dose (95 % CI: 0.2, 2.5). Associations were attenuated at the second cycle post-vaccination. We did not observe strong associations between COVID-19 vaccination and cycle regularity, bleed length, heaviness of bleed, or menstrual pain. In conclusion, COVID-19 vaccination was associated with a ∼1 day temporary increase in menstrual cycle length, but was not appreciably associated with other menstrual cycle characteristics.     

Anaphylaxis rates following mRNA COVID-19 vaccination in children and adolescents: Analysis of data reported to EudraVigilance

AimThe present study aimed to estimate the anaphylaxis rates following mRNA COVID-19 vaccination in children and adolescents in Europe.MethodsWe retrieved data on 371 anaphylaxis cases following mRNA COVID-19 vaccination in children ≤ 17 years old notified to EudraVigilance as of October 8, 2022. Overall, 27,120,512 doses of BNT162b2 vaccine and 1,400,300 doses of mRNA-1273 vaccine have been delivered to children during the study period.ResultsThe overall mean anaphylaxis rate was 12.81 [95% confidence interval (CI): 11.49–14.12] per 10⁶ mRNA vaccine doses [12.14 (95% CI: 6.37–17.91) per 10⁶ doses for mRNA-1273 and 12.84 (95% CI: 11.49–14.19) per 10⁶ doses for BNT162b2]. Children 12–17 years old accounted for 317 anaphylaxis cases, followed by 48 cases in children 3–11 years old, and 6 cases in children 0–2 years old. Children 10–17 years old had a mean anaphylaxis rate of 13.52 (95% CI: 12.03–15.00) cases per 10⁶ mRNA vaccine doses and children 5–9 years old had a mean anaphylaxis rate of 9.51 (95% CI: 6.82–12.20) cases per 10⁶ mRNA vaccine doses. There were two fatalities, both in the 12–17 years age group. The fatal anaphylaxis rate was 0.07 cases per 10⁶ mRNA vaccine doses.ConclusionsAnaphylaxis is a rare adverse event after receiving an mRNA COVID-19 vaccine in children. Continuous surveillance of serious adverse events is needed to guide vaccination policies as we move towards SARS-CoV-2 endemicity. Larger real-world studies on COVID-19 vaccination in children, using clinical case confirmation, are imperative.     

COVID-19 vaccination in pregnant women in Sweden and Norway

Vaccines against SARS-CoV-2 are highly effective in preventing severe disease and mortality. Although pregnant women are at increased risk of severe COVID-19, vaccination uptake among pregnant women varies. We used the Swedish and Norwegian population-based health registries to identify pregnant women and to investigate background characteristics associated with not being vaccinated. In this study of 164 560 women giving birth between May 2021 and May 2022, 78% in Sweden and 87% in Norway have been vaccinated with at least one dose at delivery. Not being vaccinated while being pregnant was associated with age below 30 years, low education and income level, birth region other than Scandinavia, smoking during pregnancy, not living with a partner, and gestational diabetes. These results can assist health authorities develop targeted vaccination information to diminish vaccination inequality and prevent severe disease in vulnerable groups.     

COVID-19 related immunization disruptions in Rajasthan,India: A retrospective observational study

IntroductionGovernments around the world suspended immunization outreach to control COVID-19 spread. Many have since resumed services with an emphasis on catch-up vaccinations. This paper evaluated immunization disruptions during India’s March-May 2020 lockdown and the extent to which subsequent catch-up efforts reversed them in Rajasthan, India.MethodsIn this retrospective observational study, we conducted phone surveys to collect immunization details for 2,144 children that turned one year old between January and October 2020. We used logistic regressions to compare differences in immunization timeliness and completed first-year immunization status among children that were due immunizations just before (unexposed), during (heavily exposed), and after (post-exposure) the lockdown.ResultsRelative to unexposed children, heavily exposed children were significantly less likely to be immunized at or before 9 months (OR 0.550; 95% CI 0.367–0.824; p = 0.004), but more likely to be immunized at 10–12 months (OR 1.761; 95% CI 1.196–2.591; p = 0.004). They were also less likely to have completed their key first-year immunizations (OR 0.624; 95% CI 0.478–0.816; p = 0.001) by the time of survey. In contrast, post-exposure children showed no difference in timeliness or completed first-year immunizations relative to unexposed children, despite their younger age. First-year immunization coverage among heavily exposed children decreased by 6.9 pp to 10.4 pp (9.7% to 14.0%). Declines in immunization coverage were larger among children in households that were poorer, less educated, lower caste, and residing in COVID red zones, although subgroup comparisons were not statistically significant.ConclusionDisruptions to immunization services resulted in children missing immunization during the lockdown, but catch-up efforts after it was eased ensured many children were reached at later ages. Nevertheless, catch-up was incomplete and children due their immunizations during the lockdown remained less likely to be fully immunized 4–5 months after it lifted, even as younger cohorts due immunizations in June or later returned to pre-lockdown schedules.     

我国常态化防控阶段的新型冠状病毒肺炎本土疫情流行特点和防控经验

当前新型冠状病毒肺炎（新冠肺炎）仍在全球流行,我国疫情防控长期面临“外防输入、内防扩散”的压力。进入常态化防控阶段后,我国陆续发生多起新冠肺炎本土疫情,大部分为零星散发,少部分发生聚集或暴发。冬、春季是疫情高发季节,边境和口岸城市是高发区,重点人群主动监测是疫情早发现的有效途径。通过采取一系列综合防控措施,包括大规模核...     

COVID-19 and missed or delayed vaccination in 26 middle- and high-income countries: An observational survey

BackgroundThe COVID-19 pandemic has disrupted vaccination services and raised the risk of a global resurgence of preventable diseases. We assessed the extent of and reasons for missed or delayed vaccinations (hereafter ‘missed’) in middle- and high-income countries in the early months of the pandemic.MethodsFrom May to June 2020, participants completed an online survey on missed vaccination. Analyses separated missed childhood and adult vaccination in middle-and high-income countries.ResultsRespondents were 28,429 adults from 26 middle- and high-income countries. Overall, 9% of households had missed a vaccine, and 13% were unsure. More households in middle- than high-income countries reported missed childhood vaccination (7.6% vs. 3.0%) and missed adult vaccination (9.6% vs. 3.4%, both p < .05). Correlates of missed childhood vaccination in middle-income countries included COVID-19 risk factors (respiratory and cardiovascular diseases), younger age, male sex, employment, psychological distress, larger household size, and more children. In high-income countries, correlates of missed childhood vaccination also included immunosuppressive conditions, but did not include sex or household size. Fewer correlates were associated with missed adult vaccination other than COVID-19 risk factors and psychological distress. Common reasons for missed vaccinations were worry about getting COVID-19 at the vaccination clinic (15%) or when leaving the house (11%). Other reasons included no healthcare provider recommendation, clinic closure, and wanting to save services for others.InterpretationMissed vaccination was common and more prevalent in middle- than high-income countries. Missed vaccination could be mitigated by emphasizing COVID-19 safety measures in vaccination clinics, ensuring free and accessible immunization, and clear healthcare provider recommendations.     

Delay in childhood vaccinations during the COVID-19 pandemic

ObjectivesIn many jurisdictions, routine medical care was reduced in response to the COVID-19 pandemic. The objective of this study was to determine whether the frequency of on-time routine childhood vaccinations among children age 0–2 years was lower following the COVID-19 declaration of emergency in Ontario, Canada, on March 17, 2020, compared to prior to the pandemic.MethodsWe conducted a longitudinal cohort study of healthy children aged 0–2 years participating in the TARGet Kids! primary care research network in Toronto, Canada. A logistic mixed effects regression model was used to determine odds ratios (ORs) for delayed vaccination (> 30 days vs. ≤ 30 days from the recommended date) before and after the COVID-19 declaration of emergency, adjusted for confounding variables. A Cox proportional hazards model was used to explore the relationship between the declaration of emergency and time to vaccination.ResultsAmong 1277 children, the proportion of on-time vaccinations was 81.8% prior to the COVID-19 declaration of emergency and 62.1% after (p < 0.001). The odds of delayed vaccination increased (odds ratio = 3.77, 95% CI: 2.86–4.96), and the hazard of administration of recommended vaccinations decreased after the declaration of emergency (hazard ratio = 0.75, 95% CI: 0.60–0.92). The median vaccination delay time was 5 days (95% CI: 4–5 days) prior to the declaration of emergency and 17 days (95% CI: 12–22 days) after.ConclusionThe frequency of on-time routine childhood vaccinations was lower during the first wave of the COVID-19 pandemic. Sustained delays in routine vaccinations may lead to an increase in rates of vaccine-preventable diseases.Supplementary InformationThe online version contains supplementary material available at 10.17269/s41997-021-00601-9.     

Routine childhood vaccination programme coverage,El Salvador, 2011—In search of timeliness

While assessing immunization programmes, not only vaccination coverage is important, but also timely receipt of vaccines. We estimated both vaccination coverage and timeliness, as well as reasons for non-vaccination, and identified predictors of delayed or missed vaccination, for vaccines of the first two years of age, in El Salvador.