Analyses were conducted using SAS statistical software survey procedures (version 9.4; SAS Institute). N. Engl. Wkly. In this analysis, vaccine effectiveness was evaluated as 1 minus the odds ratio. Hospitalization rates during peak Omicron circulation (January 2022) among unvaccinated adults remained 12 times the rates among vaccinated adults who received booster or additional doses and four times the rates among adults who received a primary series, but no booster or additional dose. Fully-vaccinated in this chart meant one dose of the J&J vaccine or two doses of Pfizer or Moderna. All authors (O.Z., B.F., N.P.K., T.R., M.G., E.L., P.R., K.G., S.O., and E.L.) critically reviewed the manuscript and decided to proceed with publication. J. Med. Among children 12 to 17, the . Maternal vaccination was protective, but protection was lower during Omicron than during Delta. JAMA 326, 16291631 (2021). Libby Reeg reports grants from the Michigan Department of Health and Human Services during the conduct of the study. Am. But those countries have high vaccination rates, and there, too, Omicron has spread most quickly among younger adults. Clinical information was abstracted for 5,681 adults with COVID-19associated hospitalization during July 1, 2021January 31, 2022 (Table). Includes current treatment or recent diagnosis of an immunosuppressive condition or use of an immunosuppressive therapy during the preceding 12 months. Without the vaccines many more people would likely be in hospital. M.G. KPNC members are similar to the broad catchment population in Northern California in terms of sociodemographic characteristics34. MMWR Morb Mortal Wkly Rep 2022;71:466473. However, infants aged <6 months are not currently eligible for any currently available COVID-19 vaccines and must rely on placentally acquired immunity from their mothers. CDC. On the bias of estimates of influenza vaccine effectiveness from test-negative studies. Morb. Furthermore, it was reassuring that both the cohort and the secondary TND yielded vaccine effectiveness estimates in the same direction. First, COVID-19associated hospitalizations might have been missed because of hospital testing practices and test availability. Atlanta, GA: US Department of Health and Human Services, CDC; 2022. Our primary cohort analysis used calendar days as the underlying scale to ensure that we compared infants of vaccinated and unvaccinated mothers on the same calendar days because vaccination status during pregnancy and risk of SARS-CoV-2 infection varied over the study period. The mean age at pregnancy onset was 31.62 years (standard deviation of 4.66 years). 384, 403416 (2021). 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). Ann Intern Med 2021;174:140919. 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). of pages found at these sites. Science brief: omicron (B.1.1.529) variant. ***** 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. Baden, L. R. et al. Mountain lions, a bobcat, red foxes, black bears, and skunks represent the latest avian flu cases in mammals. During Omicron predominance, children aged <6 months accounted for 44% of hospitalizations among children ages 04 years3. Maternal vaccination with at least two doses reduced the infants risk of testing SARS-CoV-2 positive initially by 84% which decreased to 56% by 6 months of life in the Delta dominant period. Association of COVID-19 vaccination during pregnancy with incidence of SARS-CoV-2 infection in infants. 182, 825831 (2022). The rates don't account for non-vaccine-related risks, Mark Jit, professor of vaccine epidemiology at the London School of Hygiene and Tropical Medicine told Insider in an email. Dagan, N. et al. For children whose mothers received one dose before pregnancy and two doses during pregnancy, VE against infection was 89% during the first 2 months of life, 73% during the first 4 months of life, and 48% up to 6 months of life. Hospitalization rates were 10.5 times higher in the unvaccinated and 2.5 times higher in vaccinated patients with no booster than in booster recipients. 1.04-1.49) after adjusting for age, sex, and vaccine characteristics. 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. In the Omicron variant period, the effectiveness of maternal vaccination in these three age intervals was 21% (CI: 21,48), 14% (CI: 9,32) and 13% (CI: 3,26), respectively. 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. In all models, we used calendar days as the time scale to account for changes over time in SARS-CoV-2 circulation and vaccine uptake. In the US, as of the end of September 2022, almost 15 million children ages <18 years have tested positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes Coronavirus Disease 2019 (COVID-19). We monitored the seroprevalence of SARS-CoV-2 nucleocapsid (anti-N) and spike protein (anti-S) antibodies in blood donors across Canada from September 2021 to June 2022 in 202,123 . Hobbs, C. V. et al. Voysey, M., Pollard, A. J., Sadarangani, M. & Fanshawe, T. R. Prevalence and decay of maternal pneumococcal and meningococcal antibodies: a meta-analysis of type-specific decay rates. Open 5, e2233273 (2022). J. Med. https://doi.org . Pediatrics. Vaccine 35, 72977301 (2017). 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%. Gynecol. We ran separate models on the time periods associated with the Delta (7/01/2021 to 12/20/2021) and Omicron variants (12/21/2021 to 5/31/2022). Cite this article. All HTML versions of MMWR articles are generated from final proofs through an automated process. Percentages presented for demographic characteristics are weighted column percentages. Article Although hospitalization rates increased for all adults, rates were highest among unvaccinated adults and lowest among adults who had received a primary series and a booster or additional dose. Christopher A. Taylor, PhD1; Michael Whitaker, MPH1; Onika Anglin, MPH1,2; Jennifer Milucky, MSPH1; Kadam Patel, MPH1,2; Huong Pham, MPH1; Shua J. Chai, MD3,4; Nisha B. Alden, MPH5; Kimberly Yousey-Hindes, MPH6; Evan J. Anderson, MD7,8,9; Kenzie Teno, MPH10; Libby Reeg, MPH11; Kathryn Como-Sabetti, MPH12; Molly Bleecker, MA13; Grant Barney, MPH14; Nancy M. Bennett, MD15; Laurie M. Billing, MPH16; Melissa Sutton, MD17; H. Keipp Talbot, MD18; Keegan McCaffrey19; Fiona P. Havers, MD1; COVID-NET Surveillance Team (View author affiliations). 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. No other potential conflicts of interest were disclosed. endorsement of these organizations or their programs by CDC or the U.S.
Cohen-Stavi, C. J. et al. Iuliano AD, Brunkard JM, Boehmer TK, et al. By the end of December, Omicron made up 58% of all cases in the US, per Our World in Data, but Delta is thought to cause more severe disease and more hospitalizations than Omicron on average. JAMA Netw. 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. Shimabukuro, T. T. et al. In supplemental analyses by trimester of vaccination, receipt of the second dose during the second and third trimesters reduced the risk of infants testing SARS-CoV-2 positive during the Delta dominant period by 91% (95% CI: 63, 98) and 85% (95% CI: 50, 96), respectively, during the first 2 months of life, by 59% (95% CI: 21, 79) and 67% (95% CI: 37, 83) during the first 4 months of life and by 64% (95% CI:31, 81) and 53% (95% CI: 24, 71) during the first 6 months of life. Dis. The rate among adults who received a primary series, but no booster or additional dose, was three times the rate among adults who received a booster or additional dose. DOI: http://dx.doi.org/10.15585/mmwr.mm7112e2. All other authors declare no competing interests. TN and NMF validated the data. Vaccination status is based on state immunization information system data. The study was conducted among a cohort of infants born between December 15, 2020, and May 31, 2022. Estimated effectiveness of COVID-19 vaccines against omicron or delta symptomatic infection and severe outcomes. wrote the initial manuscript. Introduction: A rapid increase in COVID-19 cases due to the spread of the Delta and Omicron variants in vaccinated populations has raised concerns about the hospitalization risk associated with, and the effectiveness of, COVID-19 vaccines. With the emergence of the SARS-CoV-2 Omicron variant in late 2021, Canadian public health case/contact testing was scaled back due to high infection rates with milder symptoms in a highly vaccinated population. and statistical significance was assessed at two-sided p0.05. The population of unvaccinated adults is determined by subtracting the number of adults who received any dose of vaccine, as previously defined, from the population. By clicking Sign up, you agree to receive marketing emails from Insider Structural changes in the brain may explain the persistent fatigue and neuropsychiatric complications tied to long COVID. Percentages presented for the overall number are weighted row percentages. Data about boosters was only available for those over 50. In this analysis, we estimated the odds ratio (OR) of vaccination of mothers of infants who tested positive for SARS-CoV-2 versus infants who tested negative using logistic regression models conditioned (stratified) on the calendar date of the test so that infants testing positive on a certain day were compared to infants testing negative on that same day. Kharbanda, E. O. et al. Morb. PubMedGoogle Scholar. J. Med. Halasa, N. B. et al. O.Z., N.P.K., and B.F. conceived and designed the study. 41, e81e86 (2022). BNT162b2 vaccine effectiveness against omicron in children 5 to 11 years of age. ICU admission status was missing in 1.3% (weighted) of hospitalizations; these hospitalizations are included in other analyses. We calculated vaccine effectiveness (VE) as 100% multiplied by 1HR. Abbreviations: COVID-NET = COVID-19Associated Hospitalization Surveillance Network; ICU=intensive care unit; IMV=invasive mechanical ventilation; LTCF=long-term care facility; NA = not applicable. SARS-CoV-2 infections can result in COVID-19associated hospitalizations, even among vaccinated persons. This is in keeping with the age profile. Sign up for notifications from Insider! While Omicron caused a big spike in COVID-19 cases, vaccinated people continued to be less likely to be hospitalized than the unvaccinated. Klein, N. P. et al. Receipt of one dose especially during the third trimester was also associated with a reduced risk of infants testing positive for SARS-CoV-2 during the first 6 months of life during the Delta dominant period. The group raised concerns about a small number of Guillain-Barre syndrome cases in vaccine recipients and wanted more data, especially on efficacy in those at highest risk. We excluded these infants because we were primarily interested in estimating the effectiveness of mRNA vaccines received during pregnancy; (7) mothers who received adenovirus vector vaccines or any non-mRNA platform vaccines during pregnancy; (8) mothers who did not receive their mRNA vaccinations in accordance with CDC recommendationse.g., the timing between dose 1 and dose 2 was not within the recommended intervals; and (9) infants who did not become KPNC members within two calendar months of their birth. These trends could result in epidemic phase bias if infection severity is correlated with time from infection to test. Weekly rates among unvaccinated adults and adults who received a primary COVID-19 vaccination series with a booster or additional dose peaked at 149.8 (January 8, 2022) and 11.7 (January 22, 2022), respectively. Kim, L. et al. 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. COVID-19 vaccination coverage among pregnant women during pregnancyEight Integrated Health Care Organizations, United States, December 14, 2020-May 8, 2021. Although both approaches adjusted for the same confounding factors, the effectiveness estimates from the TND were higher than those from the cohort design, which is consistent with our previous analyses of influenza vaccine effectiveness in which we also observed that the TND tended to result in higher vaccine effectiveness estimates than did our cohort analyses30. Cookies used to track the effectiveness of CDC public health campaigns through clickthrough data. MMWR Morb Mortal Wkly Rep 2020;69:134754. Among 829 adults hospitalized during the Omicron-predominant period, 49.4% were unvaccinated, compared with 69.5% during the Delta-predominant period (p<0.01). Mortal. Severe cases may increase in the wake of holiday parties where people of all ages mixed. 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. 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 are deeply flawed. Top editors give you the stories you want delivered right to your inbox each weekday. Percentages presented were weighted to account for the probability of selection for sampled cases (3). Rates were highest among unvaccinated adults and lowest among those who had received a booster or additional dose. COVID-NET conducts population-based surveillance for laboratory-confirmed COVID-19associated hospitalizations in 99 counties across 14 states. COVID-19associated hospitalizations are those occurring among residents of a predefined surveillance catchment area who have a positive real-time reverse transcriptionpolymerase chain reaction (RT-PCR) or rapid antigen detection test result for SARS-CoV-2 during hospitalization or the 14 days preceding admission. The average death rate among Americans over age 65 who contract the flu has ranged between 1 in 75 and 1 in 160 in recent years, according to the C.D.C. 387, 227236 (2022). 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. No other exclusion criteria were applied. Hospitalisation associated with SARS-CoV-2 delta variant in Denmark. The risk of hospitalisation appeared to increase when comparing delta with alpha infections. Vaccinated patients during the Delta wave were 37% (over with two doses), while during the Omicron wave they were 57%. 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). Wkly. Wkly Rep. 71, 352358 (2022). Google Scholar. Just 28% of children in the age group - around 8 million . This was the highest age-adjusted weekly rate observed among any racial and ethnic group during the pandemic. The average age of decedents was 83.3 years. Use of trade names and commercial sources is for identification only and does not imply endorsement by the U.S. Department of
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). 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. During the Omicron period, among children whose mothers received 1 dose before pregnancy and 1 dose during pregnancy, VE against infection was 46% (95% CI: 23, 77) during the first 2 months of life, 16% (95% CI: 28, 50) during the first 4 months of life and 3% (95% CI: 32, 36) during the first 6 months of life compared with children whose mothers were unvaccinated (Supplemental Table4). 552a; 44 U.S.C. Maternal vaccination was protective, but protection was lower during the Omicron period than during Delta. 45 C.F.R. However, vaccination during pregnancy was less effective at protecting infants against SARS-CoV-2 infection during the Omicron period. Most mothers (1032 of 1138) who received only one dose received the vaccine during the third trimester. J., Fireman. Johnson AG, Amin AB, Ali AR, et al. 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). We examined the effectiveness of maternal vaccination against SARS-CoV-2 infection in 30,311 infants born at Kaiser Permanente Northern California from December 15, 2020, to May 31, 2022. J. Med. 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). The cumulative monthly age-adjusted hospitalization rate during January 2022 among unvaccinated adults (528.2) was 12 times the rates among those who had received a booster or additional dose (45.0) and four times the rates among adults who received a primary series, but no booster or additional dose (133.5). N. Engl. Finally, we conducted additional supplemental analyses to estimate VE among children whose mothers received at least one vaccine dose prior to pregnancy onset and at least one dose during pregnancy. Sect. Moline HL, Whitaker M, Deng L, et al. All adjustment variables were selected a priori based on prior work36. Adults who completed a primary vaccination series were persons who had received the second dose of a 2-dose COVID-19 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 or additional dose. These data should be taken with a grain of salt. Hospitalization rates and characteristics of children aged <18 years hospitalized with laboratory-confirmed COVID-19COVID-NET, 14 States, March 1-July 25, 2020. Published by Elsevier Ltd. Users are referred to the electronic PDF version (https://www.cdc.gov/mmwr)
For infants, we included age, as a categorical time-changing variable in 30-day increments. From this cohort, the study excluded the following infants born to (1) mothers who were not between ages 16 and 50 years at pregnancy onset; (2) mothers who did not have a primary KPNC facility assignment; (3) mothers who were not continuous KPNC members from December 15, 2020 until delivery; (4) mothers who had a positive nasal/throat swab for SARS-CoV-2 by polymerase chain reaction (PCR) prior to pregnancy onset; (5) mothers who had a positive SARS-CoV-2 antibody test documented by KPNC prior to the onset of pregnancy; (6) mothers who received one or more doses of COVID-19 vaccine prior to pregnancy onset. Access your favorite topics in a personalized feed while you're on the go. Perm. To ensure stability and reliability of rates by vaccination status, data are presented beginning when 14 days have passed since at least 5% of the population of adults aged 18 years in the COVID-NET surveillance catchment area had received an additional or booster dose.