As Omicron spread in the US, hospitalization rates in December were much lower for the vaccinated. 1). Protection during both periods decreased as infants aged. Infect. Suggested citation for this article: Taylor CA, Whitaker M, Anglin O, et al. Effectiveness of COVID-19 vaccines in preventing hospitalization among adults aged 65 yearsCOVID-NET, 13 states, FebruaryApril 2021. We used two different study designs: a primary design using a cohort analysis in which infants of vaccinated pregnant persons were compared with infants of unvaccinated pregnant persons. Rates were highest among unvaccinated adults and lowest among those who had received a booster or additional dose. Further information on research design is available in theNature Portfolio Reporting Summary linked to this article. endorsement of these organizations or their programs by CDC or the U.S. We observed that infants protection through vaccination during pregnancy decreased as they aged from 2 months to 6 months. Users are referred to the electronic PDF version (https://www.cdc.gov/mmwr) In this large study which included >30,000 infants, we found that receipt of at least two doses of mRNA COVID-19 vaccine during pregnancy was associated with a decreased risk of infants testing SARS-CoV-2 positive during their first 6 months of life. Iowa does not provide data on vaccination status. In addition, our study period included two different SARV-CoV-2 variants, which allowed estimation of the effectiveness of vaccination during pregnancy in infants during both the Delta and Omicron variant periods. Vaccinated patients during the Delta wave were 37% (over with two doses), while during the Omicron wave they were 57%. During the Omicron-predominant period, peak hospitalization rates among non-Hispanic Black (Black) adults were nearly four times the rate of non-Hispanic White (White) adults and was the highest rate observed among any racial and ethnic group during the pandemic. N. Engl. 139, e20164091 (2017). * https://covid.cdc.gov/covid-data-tracker/#variant-proportions, https://www.cdc.gov/coronavirus/2019-ncov/covid-data/covid-net/purpose-methods.html. SARS-CoV-2 infection and COVID-19 vaccination rates in pregnant women in Scotland, Effectiveness of the BNT162b2 mRNA COVID-19 vaccine in pregnancy, Effectiveness of a third BNT162b2 mRNA COVID-19 vaccination during pregnancy: a national observational study in Israel, Covid-19 vaccination programme effectiveness against SARS-CoV-2 related infections, hospital admissions and deaths in the Apulia region of Italy: a one-year retrospective cohort study, Post-vaccination outcomes in association with four COVID-19 vaccines in the Kingdom of Bahrain, Effectiveness and protection duration of Covid-19 vaccines and previous infection against any SARS-CoV-2 infection in young adults, The indirect effect of mRNA-based COVID-19 vaccination on healthcare workers unvaccinated household members, SARS-CoV-2 infection and COVID-19 vaccination in pregnancy, Duration of mRNA vaccine protection against SARS-CoV-2 Omicron BA.1 and BA.2 subvariants in Qatar, https://downloads.aap.org/AAP/PDF/AAP%20and%20CHA%20-%20Children%20and%20COVID-19%20State%20Data%20Report%209.29.22%20FINAL.pdf?_ga=2.255000394.335550773.1665001859-370326403.1636740765, https://doi.org/10.1016/j.jpeds.2022.09.059, http://creativecommons.org/licenses/by/4.0/. KPNC has a comprehensive electronic health record system (Kaiser Permanente HealthConnect, a customized EPIC system), that captures detailed information on all medical services, including immunization, membership enrollment including place of residence, demographics, and pregnancy-related care from pregnancy onset to delivery, and beyond. J. However, data currently available on the persistence of immunity after vaccination on the one hand and the emergence of viral variants with reduced sensibility to vaccine immunity on the other, raise the need to administer boosters to maintain the protection and to compare . Over the entire study period, the incidence of hospitalization for COVID-19 was lower during the first 6 months of life among infants of vaccinated mothers compared with infants of unvaccinated mothers (21/100,000 person-years vs. 100/100,000 person-years). Questions or messages regarding errors in formatting should be addressed to All authors reviewed the manuscript. In the meantime, to ensure continued support, we are displaying the site without styles Google Scholar. CDC is not responsible for Section 508 compliance (accessibility) on other federal or private website. Adults who received booster doses were classified as those who completed their primary vaccination series and received an additional or booster dose of vaccine on or after August 13, 2021, at any time after the completion of their primary series, and 14 days before a positive test result for SARS-CoV-2, because COVID-19associated hospitalizations are a lagging indicator, and time passed after receipt of a booster dose has been shown to be associated with reduced rates of COVID-19 infection (https://www.nejm.org/doi/full/10.1056/NEJMoa2114255). During the study period, the omicron variant experienced a rapidly increasing incidence, whereas the delta variant was experiencing a decreasing or less rapidly increasing incidence. On 13 December, Denmark released data showing that hospitalization rates for people infected with Omicron seemed to be on a par with those for people infected with other variants. https://www.cdc.gov/mmwr/volumes/70/wr/mm7050e2.htm, Adults who completed their primary COVID-19 vaccination series were defined as those who had received the second dose of a 2-dose primary vaccination series or a single dose of a 1-dose primary vaccine product 14 days before receipt of a positive SARS-CoV-2 test result associated with their hospitalization but received no additional or booster dose. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate. Sample sizes presented are unweighted with weighted percentages. Vaccinated patients were older (68 vs. 57 years), and 62% had at least one comorbidity Admission to the ICU was 20%, and the mortality rate at 30 days was 14%. O.Z. as well as other partner offers and accept our. The outcomes were the infants first positive nasal/throat swab for SARS-CoV-2 by PCR, and the first COVID-19-related hospitalization, occurring during the first 6 months of life and recorded in the electronic health record. (2021) Omicron is supercharging the COVID vaccine booster debate. Selected counties in California, Colorado, Connecticut, Georgia, Iowa, Maryland, Michigan, Minnesota, New Mexico, New York, Ohio, Oregon, Tennessee, and Utah (https://www.cdc.gov/mmwr/volumes/69/wr/mm6915e3.htm). All HTML versions of MMWR articles are generated from final proofs through an automated process. Kharbanda, E. O. et al. The vaccines have proved highly safe and effective at reducing the risk of severe illness, hospitalization and death. Partially vaccinated adults, and those who received a single dose of a 1-dose product <14 days before the positive SARS-CoV-2 test result were not included in analyses by vaccination status but were included in rates and overall proportions that were not stratified by vaccination status. However, these Omicron impacts have been mostly observed in countries with high vaccination rates in the Region: the comparatively lower rate of hospitalizations and deaths so far is in large part thanks to vaccination, particularly of vulnerable groups. Urban Health 83, 10411062 (2006). Evaluation of acute adverse events after Covid-19 vaccination during pregnancy. The exposure of interest was mRNA COVID-19 vaccination status during pregnancy in the electronic health record. 20, 15225 (2016). NMF, MC, GD, DDA, AMP, and ST handled project administration. Maternal vaccination and risk of hospitalization for Covid-19 among infants. A free-text field for other types of residences was examined; patients with an LTCF-type residence were also categorized as LTCF residents. We observed a similar pattern in vaccine effectiveness by trimester during the Omicron dominant period, however, estimates of vaccine effectiveness by trimester were imprecise and much lower than during the Delta period (Table3). Jackson, M. L. & Nelson, J. C. The test-negative design for estimating influenza vaccine effectiveness. The TND, a case-control study, has been commonly used in studies of the effectiveness of influenza vaccines and more recently COVID-19 vaccines. Despite several studies showing that vaccination during pregnancy is safe for pregnant people24,25,26,27,28, vaccine uptake has been suboptimal in this group29. Requests for access to the underlying source data should be directed to UKHSA. pdf files, Omicron: fewer adverse outcomes come with new dangers, Statement on offensive historical content, Redistribute or republish the final article, Reuse portions or extracts from the article in other works. For infants, we included age, as a categorical time-changing variable in 30-day increments. Hospitalisation associated with SARS-CoV-2 delta variant in Denmark. Omicron is super infectious, and about 20% of people in the United States over the age of 5 as well as all children under 5 remain unvaccinated. If you do not allow these cookies we will not know when you have visited our site, and will not be able to monitor its performance. Hospitalizations rates increased among all adults irrespective of vaccination status (unvaccinated, primary series only, or primary series plus a booster or additional dose). Nature Communications thanks Annette Regan, Olof Stephansson and the other, anonymous, reviewer(s) for their contribution to the peer review of this work. Percentages presented were weighted to account for the probability of selection for sampled cases (3). and statistical significance was assessed at two-sided p0.05. Late last year, as Omicron was spreading fast in the US, hospitalization rates per 100,000 rose sharply among unvaccinated adults, while rates in those who were fully vaccinated remained. Children currently account for about 18.5% of reported COVID-19 cases in the United States1. Vaccine 31, 31043109 (2013). 387, 227236 (2022). Selected counties in California, Colorado, Connecticut, Georgia, Iowa, Maryland, Michigan, Minnesota, New Mexico, New York, Ohio, Oregon, Tennessee, and Utah (https://www.cdc.gov/mmwr/volumes/69/wr/mm6915e3.htm). 1.04-1.49) after adjusting for age, sex, and vaccine characteristics. PubMed Mothers were classified as either having had 2 doses or one dose of mRNA COVID-19 vaccines during pregnancy (and completed more than 14 days prior to delivery) or not having had any COVID-19 vaccines prior to delivery. Vaccinations were limited only to those received during pregnancy. In our primary analysis, we implemented a cohort study design where we used Cox proportional hazards models that allow for time-varying covariates to estimate the SARS-CoV-2 infection hazard ratio (HR) in infants of mothers vaccinated with at least 2 doses of mRNA COVID-19 vaccines during pregnancy and 1 dose only versus mothers who were unvaccinated during pregnancy. Sect. 383, 26032615 (2020). The prevalence of primary COVID-19 vaccination and of receipt of a booster dose were lower among Black adults compared with White adults. PubMedGoogle Scholar. PubMed Central The efficacy of COVID 19 vaccines for reducing the risk of severe COVID-19 infection is demonstrated in real life. While this proportion might not be representative of the proportion of vaccinated pregnant women within KPNC because of our exclusion criteria, more efforts are needed to promote COVID-19 vaccines for pregnant persons because vaccination provides protection to mothers and their infants until they are old enough to receive their own COVID-19 vaccines. Atlanta, GA: US Department of Health and Human Services, CDC; 2022. Risk was especially high for people with severe combined immunodeficiency (HR, 6.2). Maternal SARS-CoV-2 vaccination and infant protection against SARS-CoV-2 during the first six months of life, https://doi.org/10.1038/s41467-023-36547-4. NMF, MC, GD, DDA, AMP, and ST supervised the work. Data from the COVID-19Associated Hospitalization Surveillance Network (COVID-NET) were analyzed to compare COVID-19associated hospitalization rates among adults aged 18 years during B.1.617.2 (Delta; July 1December 18, 2021) and Omicron (December 19, 2021January 31, 2022) variant predominance, overall and by race/ethnicity and vaccination status. N. Engl. Maternal SARS-CoV-2 vaccination and infant protection against SARS-CoV-2 during the first six months of life. Top editors give you the stories you want delivered right to your inbox each weekday. We use cookies to help provide and enhance our service and tailor content and ads. However, a milder virus could still put pressure . The difference between the two studies might be due to population characteristics and the timing of follow-up as ours went through May 31, 2022, while the Norwegian study ended in April 2022. Maternal vaccination was protective, but protection was lower during the Omicron period than during Delta. This preceded and had no relation to COVID-19, and GD had no role in and received no funding from the project. COVID-19 incidence and death rates among unvaccinated and fully vaccinated adults with and without booster doses during periods of Delta and Omicron variant emergence25 U.S. Jurisdictions, April 4December 25, 2021. Overall, 63% of Americans are fully vaccinated. Science brief: omicron (B.1.1.529) variant. Children and COVID-19: state data report. We calculated vaccine effectiveness (VE) as 100% multiplied by 1HR. ***** An additional 172 (3.4%, 95% CI=2.7%4.2%) adults were partially vaccinated, 69 (0.9%, 95% CI=0.61.2) received a primary vaccination series <14 days before a positive for SARS-CoV-2 test result, and 186 (4.1%) had unknown vaccination status; these groups are not further described in this analysis. CIDRAP - Center for Infectious Disease Research & Policy Corresponding author: Christopher A. Taylor, iyq3@cdc.gov. Adults who received booster doses were classified as those who completed the primary series and received an additional or booster dose on or after August 13, 2021, at any time after completion of the primary series, and 14 days before a positive test result for SARS-CoV-2, as COVID-19associated hospitalizations are a lagging indicator and time passed after receipt of a booster dose has been shown to be associated with reduced rates of COVID-19 infection (https://www.nejm.org/doi/full/10.1056/NEJMoa2114255). BNT162b2 mRNA Covid-19 vaccine in a nationwide mass vaccination setting. Morb. https://www.cdc.gov/nchs/nvss/bridged_race.htm, ** https://www.medrxiv.org/content/10.1101/2021.08.27.21262356v1, On August 13, 2021, CDCs Advisory Committee on Immunization Practices (ACIP) issued the first of several recommendations for additional or booster doses of COVID-19 vaccine. Morb. Protection during both periods decreased as infants aged from 2 months to 6 months. Using previously described methods (3), investigators collected clinical data on a representative sample of adult patients (7.9%) hospitalized during July 1, 2021January 31, 2022, stratified by age and COVID-NET site. Initial hospital data from England and Denmark also suggest Omicron cases are less severe. The study was conducted among a cohort of infants born between December 15, 2020, and May 31, 2022. Over the entire study period, the crude rate of hospitalization with a SARS-CoV-2 positive test was lower during the first 6 months of life among infants whose mothers received at least two doses of mRNA COVID-19 vaccines during pregnancy compared with infants whose mothers were unvaccinated during pregnancy (21/100,000 PY vs. 100/100,000 PY). Sect. According to the Ontario Science Table's online dashboard, the hospital occupancy rate for the unvaccinated was 611 per million unvaccinated people in the province's population as of Jan. 7,. If ethnicity was unknown, non-Hispanic ethnicity was assumed. Accessed March 10, 2022. Estimated effectiveness of COVID-19 vaccines against omicron or delta symptomatic infection and severe outcomes. SARS-CoV-2 variant data update, England: Version 21. Carlsen, E. O. et al. Data among adults over 50 showed that a booster shot gave even stronger protection. Durability of anti-spike antibodies in infants after maternal COVID-19 vaccination or natural infection. It is possible that this practice may have led to some misclassification of the outcome, and we were unable to assess whether this misclassification was differential between vaccinated and unvaccinated mothers. During the Omicron dominant period, receipt of 2 doses during pregnancy reduced the risk of the infant testing SARS-CoV-2 positive by 21% (95% CI: 21, 48) during the first 2 months of life, 14% (95% CI: 8, 32) during the first 4 months of life, and 13% (95% CI: 3, 26) during the first 6 months of life (Table2). J. Med. Starting the week ending December 4, 2021, Maryland data are not included in weekly rate calculations but are included in previous weeks. CDC twenty four seven. The objective of this study was to further evaluate the effectiveness of at least two doses of mRNA COVID-19 vaccination during pregnancy for preventing SARS-CoV-2 infection in infants during the first 2, 4, and 6 months of life during the Delta and Omicron variant periods. Implementing strategies that result in the equitable receipt of COVID-19 vaccinations among persons with disproportionately higher hospitalizations rates, including non-Hispanic Black adults, is an urgent public health priority. GD declares that his employer UK Health Security Agency (previously operating as Public Health England) received funding from GlaxoSmithKline for a research project related to influenza antiviral treatment. Selected counties in California, Colorado, Connecticut, Georgia, Iowa, Maryland, Michigan, Minnesota, New Mexico, New York, Ohio, Oregon, Tennessee, and Utah (https://www.cdc.gov/mmwr/volumes/69/wr/mm6915e3.htm). Still, even with a smaller percentage of people getting severely ill during the Omicron wave, a large number of cases over a short time can lead to a spike in people being hospitalized or admitted . O.Z., N.P.K., and B.F. conceived and designed the study. 384, 21872201 (2021). 3501 et seq. Dagan, N. et al. Stay up to date with your COVID-19 vaccines. part 46, 21 C.F.R. Nat Commun 14, 894 (2023). Iuliano AD, Brunkard JM, Boehmer TK, et al. These data should be taken with a grain of salt. Our findings that receipt of at least two doses of COVID-19 vaccine during pregnancy was effective at protecting infants during the Delta period are similar to those reported in a recent Norwegian study showing that mRNA COVID-19 vaccination during pregnancy was associated with a 71% decreased risk of testing positive for SARS-CoV-2 in infants during their first 4 months of life during the Delta period17. * Adults who completed a primary vaccination series were defined as those who had received the second dose of a 2-dose primary vaccination series or a single dose of a 1-dose product 14 days before a positive SARS-CoV-2 test associated with their hospitalization but received no booster dose. But those countries have high vaccination rates, and there, too, Omicron has spread most quickly among younger adults. https://downloads.aap.org/AAP/PDF/AAP%20and%20CHA%20-%20Children%20and%20COVID-19%20State%20Data%20Report%209.29.22%20FINAL.pdf?_ga=2.255000394.335550773.1665001859-370326403.1636740765 (2022). Lipkind, H. S. et al. The TND is designed to better control for bias related to health care-seeking behavior31,32. Coinciding with Omicron variant predominance, COVID-19associated hospitalization rates among adults increased in late December 2021 and peaked in January 2022; rates increased more among Black adults relative to rates among adults of other racial and ethnic groups. This is consistent with data showing the incidence of positive SARS-CoV-2 test results or death from COVID-19 is higher among unvaccinated adults and adults who have not received a booster than among those who have received a booster or additional dose (5). Taken together, these findings suggest that the increased risk for hospitalization among Black adults during the Omicron-predominant period might also be due, in part, to lower proportions of Black adults receiving both the primary vaccination series and booster doses. 189, 13791388 (2020). Surveillance officers abstracted data on sampled patients from medical charts. Adults who received booster doses were classified as those who completed the primary series and received an additional or booster dose on or after August 13, 2021, at any time after completion of the primary series, and 14 days before a positive test result for SARS-CoV-2, because COVID-19associated hospitalizations are a lagging indicator and time passed after receipt of a booster dose has been shown to be associated with reduced rates of COVID-19 infection (https://www.nejm.org/doi/full/10.1056/NEJMoa2114255). PubMed The finding that maternal vaccination was less effective at protecting infants during the Omicron dominant period is also consistent with previous studies which have reported decreased effectiveness of mRNA COVID-19 vaccines during Omicron among children and adults14,20. Morb. In the TND, we estimated that during the Delta predominant period, maternal vaccination with at least doses reduced the infants risk of testing SARS-CoV-2 positive by 95% (95% CI:76, 99) during the first 2 months of life, 70% (95% CI: 52, 82) during the first 4 months of life, and 61% (95% CI: 42, 74) during the first 6 months of life (Supplemental Table2). Effectiveness of BNT162b2 vaccination during pregnancy in preventing hospitalization for SARS-CoV-2 in infants. Hospitalization rates and characteristics of children aged <18 years hospitalized with laboratory-confirmed COVID-19COVID-NET, 14 States, March 1-July 25, 2020. 9-14 As of October 2022, 68% of the US population has completed primary series vaccination. The University of Minnesota is an equal opportunity educator and employer, Office of the Vice President for Research | Contact U of M | Privacy Policy, Mary Van Beusekom | News Writer | CIDRAP News, Two recent papers claim there are no differences between surgical masks and respirators for preventing the spread of respiratory diseases like COVID-19 and flu, but the articles. https://medrxiv.org/cgi/content/short/2021.08.27.21262356v1. Vaccine effectiveness for 1 dose during the first 6 months of life was 68% (95% CI: 12, 88) (Table2). Two to 4 weeks after a booster dose, vaccine effectiveness ranged from around 65-75%, dropped to 55-70% at 5 to 9 weeks, and 40-50% from 10 weeks or more after a booster dose. No other exclusion criteria were applied. Monthly incidence is based on SARS-CoV-2 positive test result date or, if not known, hospital admission date. Omicron data in UK is 'enormously worrying,' immunologist says "In the last two weeks, no fewer than 80% of admissions were below the age of 50 years. SARS-CoV-2 variants of concern and variants under investigation in England: technical briefing 35. Nursing home residents have been disproportionately affected by COVID-19; older age, comorbidities, and the congregate nature of nursing homes place residents at higher risk for infection and severe COVID-19-associated outcomes . We thank staff at UKHSA and members of the UK Government SPI-M committee and the UKHSA Variant Technical Group for valuable discussions. COVID-19 vaccines have demonstrated both high efficacy in clinical trials and high real-world effectiveness, especially against the original and Delta variant of the virus6,7,8,9,10. To obtain Pediatr. We, therefore, were unable to assess whether maternal infection provided some protection to their infants. Our study was strengthened both by its large sample size and our ability to follow infants through 6 months of age. E. & Klein, N. P. Effectiveness of vaccination during pregnancy to prevent infant pertussis. MB), Help with During the Omicron dominant period, maternal vaccination with at least two doses reduced the infants risk of testing SARS-CoV-2 positive by 43% (95% CI: 4, 69) during the first 2 months of life, 36% (95% CI:11, 55) during the first 4 months of life, and 41% (95% CI: 25, 53) during the first 6 months of life (Supplemental Table2). Like influenza and Tdap vaccines15,16, data suggest that vaccination during pregnancy may protect infants who are not old enough to be vaccinated against COVID-19. Libby Reeg reports grants from the Michigan Department of Health and Human Services during the conduct of the study. J. Med. Messer, L. C. et al. **** ICU admission and IMV are not mutually exclusive categories, and patients could have received both. We conducted a descriptive analysis of the study population and calculated crude rates of SARS-CoV-2 infection and hospitalization by maternal vaccination status.