The Omicron wave and the waning of COVID-19 vaccine effectiveness. Influence of vaccine booster and age on confirmed infection incidence.
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ABSTRACT:
SUBMITTER: Corral-Gudino L
PROVIDER: S-EPMC9132883 | biostudies-literature | 2022 Aug
REPOSITORIES: biostudies-literature
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The Omicron wave and the waning of COVID-19 vaccine effectiveness. Influence of vaccine booster and age on confirmed infection incidence.
Corral-Gudino Luis L Del-Amo-Merino María Piedad MP Eiros-Bouza José María JM García-Cruces-Méndez Jesús Fernando JF Domínguez-Gil González Marta M
European journal of internal medicine 20220526
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Project description:BackgroundAlthough many people received the COVID-19 vaccine, shortly after the Chinese government announced that the three-year COVID-19 restrictions were being eased, the first large number of Omicron infections appeared in Beijing. We describe epidemiological characteristics, clinical severity, and time-to-event distribution of patients infected with SARS-CoV-2 in Beijing Omicron outbreak, comparing those who received the booster vaccine with cases of full-course/partial-course vaccines.MethodsWe collected epidemiological, clinical, laboratory, and clinical management data from the hospital information system (HIS) for 1495 cases during Dec 2022-Jan 2023. We also collected illness onset time, diagnosis time, hospital admission time, and start and end times of each treatment. In addition, we collected the time of vaccination, inoculation times, and type of COVID-19 vaccination thorough the vaccination system. We described the epidemiological characteristics across vaccine inoculation doses, and estimated the risk of death, mechanical ventilation, and admission to the intensive care unit for patients admitted to hospital. We used the Kaplan-Meier method to estimate the survival rate and plot the survival curve, and the Cox proportional hazards model to assess the effect of covariates on survival time.ResultsOf the 1495 cases, 58.1% were male. The median ages in the non-vaccinated and vaccinated groups were 80 and 47 years. Elderly with underlying medical conditions and lower BMI less willing to vaccinate(p < 0.05). Both the inactivated vaccine and adenovirus vaccine could reduce clinical severity and prolong survival time, and the protective effect of booster vaccination was the best. The clinical severity increased linearly from the booster vaccinated group to the full-course vaccinated group and non-vaccinated groups, and the death risk of COVID-19 cases without vaccination was the highest.ConclusionBooster vaccines of COVID-19 can provide greater protection against severe illness and death, and continuous monitoring and regular assessment are needed to minimize the risk of a recurrence of the pandemic.
| S-EPMC11600739 | biostudies-literature
Project description:We estimated the effectiveness of booster doses of monovalent mRNA COVID-19 vaccines against Omicron-associated severe outcomes among adults in Ontario, Canada. We used a test-negative design to estimate vaccine effectiveness (VE) against hospitalization or death among SARS-CoV-2-tested adults aged ≥50 years from January 2 to October 1, 2022, stratified by age and time since vaccination. We also compared VE during BA.1/BA.2 and BA.4/BA.5 sublineage predominance. We included 11,160 cases and 62,880 tests for test-negative controls. Depending on the age group, compared to unvaccinated adults, VE was 91-98% 7-59 days after a third dose, waned to 76-87% after ≥240 days, was restored to 92-97% 7-59 days after a fourth dose, and waned to 86-89% after ≥120 days. VE was lower and declined faster during BA.4/BA.5 versus BA.1/BA.2 predominance, particularly after ≥120 days. Here we show that booster doses of monovalent mRNA COVID-19 vaccines restored strong protection against severe outcomes for at least 3 months after vaccination. Across the entire study period, protection declined slightly over time, but waned more during BA.4/BA.5 predominance.
| S-EPMC9990563 | biostudies-literature
Project description:The BNT162b2 COVID-19 vaccine has been shown to reduce viral load of breakthrough infections (BTIs), an important factor affecting infectiousness. This viral-load protective effect has been waning with time post the second vaccine and later restored with a booster shot. It is currently unclear though for how long this regained effectiveness lasts. Analyzing Ct values of SARS-CoV-2 qRT-PCR tests of over 22,000 infections during a Delta-variant-dominant period in Israel, we find that this viral-load reduction effectiveness significantly declines within months post the booster dose. Adjusting for age, sex and calendric date, Ct values of RdRp gene initially increases by 2.7 [CI: 2.3-3.0] relative to unvaccinated in the first month post the booster dose, yet then decays to a difference of 1.3 [CI: 0.7-1.9] in the second month and becomes small and insignificant in the third to fourth months. The rate and magnitude of this post-booster decline in viral-load reduction effectiveness mirror those observed post the second vaccine. These results suggest rapid waning of the booster's effectiveness in reducing infectiousness, possibly affecting community-level spread of the virus.
| S-EPMC8897467 | biostudies-literature
Project description:BackgroundIn the United States, it is recommended that healthcare providers offer influenza vaccination by October, if possible. However, if the vaccine's effectiveness soon begins to wane, the optimal time for vaccination may be somewhat later. We examined whether the effectiveness of influenza vaccine wanes during the influenza season with increasing time since vaccination.MethodsWe identified persons who were vaccinated with inactivated influenza vaccine from 1 September 2010 to 31 March 2017 and who were subsequently tested for influenza and respiratory syncytial virus (RSV) by a polymerase chain reaction test. Test-confirmed influenza was the primary outcome and days-since-vaccination was the predictor of interest in conditional logistic regression. Models were adjusted for age and conditioned on calendar day and geographic area. RSV was used as a negative-control outcome.ResultsCompared with persons vaccinated 14 to 41 days prior to being tested, persons vaccinated 42 to 69 days prior to being tested had 1.32 (95% confidence interval [CI], 1.11 to 1.55) times the odds of testing positive for any influenza. The odds ratio (OR) increased linearly by approximately 16% for each additional 28 days since vaccination. The OR was 2.06 (95% CI, 1.69 to 2.51) for persons vaccinated 154 or more days prior to being tested. No evidence of waning was found for RSV.ConclusionsOur results suggest that effectiveness of inactivated influenza vaccine wanes during the course of a single season. These results may lead to reconsideration of the optimal timing of seasonal influenza vaccination.
| S-EPMC7182205 | biostudies-literature
Project description:BackgroundDeveloping accurate and reliable methods to estimate vaccine protection is a key goal in immunology and public health. While several statistical methods have been proposed, their potential inaccuracy in capturing fast intraseasonal waning of vaccine-induced protection needs to be rigorously investigated.MethodsTo compare statistical methods for estimating vaccine effectiveness (VE), we generated simulated data using a multiscale, agent-based model of an epidemic with an acute viral infection and differing extents of VE waning. We apply a previously proposed framework for VE measures based on the observational data richness to assess changes of vaccine-induced protection over time.ResultsWhile VE measures based on hard-to-collect information (eg, the exact timing of exposures) were accurate, usually VE studies rely on time-to-infection data and the Cox proportional hazards model. We found that its extension using scaled Schoenfeld residuals, previously proposed for capturing VE waning, was unreliable in capturing both the degree of waning and its functional form and identified the mathematical factors contributing to this unreliability. We showed that partitioning time and including a time-vaccine interaction term in the Cox model significantly improved estimation of VE waning, even in the case of dramatic, rapid waning. We also proposed how to optimize the partitioning scheme.ConclusionsWhile appropriate for rejecting the null hypothesis of no waning, scaled Schoenfeld residuals are unreliable for estimating the degree of waning. We propose a Cox-model-based method with a time-vaccine interaction term and further optimization of partitioning time. These findings may guide future analysis of VE waning data.
| S-EPMC10169445 | biostudies-literature
Project description:BackgroundThe current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccines may be less effective against the Omicron variant than against earlier variants. With recent resurgence of SARS-CoV-2 cases, the role of booster doses of the vaccine needs to be highlighted.MethodsUsing a retrospective cohort study design emulating a target trial, we determined the relative vaccine effectiveness (RVE) of a homologous booster dose of a SARS-CoV-2 messenger RNA (mRNA) vaccine compared with the primary vaccine series alone in preventing infection, hospitalization, and intensive care unit admission, and death in the Department of Veterans Affairs healthcare system in the United States. Among infection-free survivors who received 2 doses of a mRNA vaccine before 30 April 2021, we identified those who received a booster between 22 September and 25 December 2021 and matched them 1:1 with individuals who did not receive a booster.ResultsAmong 2 384 272 previously uninfected persons with 2 doses of an mRNA vaccine by 30 April 2021, we identified 462 950 booster recipients between 22 September and 25 December 2021, who were matched 1:1 with non-booster recipients. The RVE (95% confidence interval) was 19% (17%-22%) for confirmed infection, 52% (46%-57%) for hospitalization, and 83% (65%-92%) for intensive care unit admission or death. Recipients of the mRNA-1273 vaccine had a lower cumulative incidence of infections and hospitalizations than recipients of the BNT162b2 vaccine (log-rank P <.001 for both comparisons).ConclusionsWhile the RVE of SARS-CoV-2 mRNA booster vaccine dose in preventing infection against the Omicron variant is low, it is substantial in preventing hospitalization and high in preventing the most severe/critical disease.
| S-EPMC11487159 | biostudies-literature
Project description:BackgroundThe safety and immunogenicity of the bivalent omicron-containing mRNA-1273.214 booster vaccine are not known.MethodsIn this ongoing, phase 2-3 study, we compared the 50-μg bivalent vaccine mRNA-1273.214 (25 μg each of ancestral Wuhan-Hu-1 and omicron B.1.1.529 [BA.1] spike messenger RNAs) with the previously authorized 50-μg mRNA-1273 booster. We administered mRNA-1273.214 or mRNA-1273 as a second booster in adults who had previously received a two-dose (100-μg) primary series and first booster (50-μg) dose of mRNA-1273 (≥3 months earlier). The primary objectives were to assess the safety, reactogenicity, and immunogenicity of mRNA-1273.214 at 28 days after the booster dose.ResultsInterim results are presented. Sequential groups of participants received 50 μg of mRNA-1273.214 (437 participants) or mRNA-1273 (377 participants) as a second booster dose. The median time between the first and second boosters was similar for mRNA-1273.214 (136 days) and mRNA-1273 (134 days). In participants with no previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the geometric mean titers of neutralizing antibodies against the omicron BA.1 variant were 2372.4 (95% confidence interval [CI], 2070.6 to 2718.2) after receipt of the mRNA-1273.214 booster and 1473.5 (95% CI, 1270.8 to 1708.4) after receipt of the mRNA-1273 booster. In addition, 50-μg mRNA-1273.214 and 50-μg mRNA-1273 elicited geometric mean titers of 727.4 (95% CI, 632.8 to 836.1) and 492.1 (95% CI, 431.1 to 561.9), respectively, against omicron BA.4 and BA.5 (BA.4/5), and the mRNA-1273.214 booster also elicited higher binding antibody responses against multiple other variants (alpha, beta, gamma, and delta) than the mRNA-1273 booster. Safety and reactogenicity were similar with the two booster vaccines. Vaccine effectiveness was not assessed in this study; in an exploratory analysis, SARS-CoV-2 infection occurred in 11 participants after the mRNA-1273.214 booster and in 9 participants after the mRNA-1273 booster.ConclusionsThe bivalent omicron-containing vaccine mRNA-1273.214 elicited neutralizing antibody responses against omicron that were superior to those with mRNA-1273, without evident safety concerns. (Funded by Moderna; ClinicalTrials.gov number, NCT04927065.).
| S-EPMC9511634 | biostudies-literature
Project description:BackgroundLimited evidence is available on the real-world effectiveness of the BNT162b2 vaccine against coronavirus disease 2019 (Covid-19) and specifically against infection with the omicron variant among children 5 to 11 years of age.MethodsUsing data from the largest health care organization in Israel, we identified a cohort of children 5 to 11 years of age who were vaccinated on or after November 23, 2021, and matched them with unvaccinated controls to estimate the vaccine effectiveness of BNT162b2 among newly vaccinated children during the omicron wave. Vaccine effectiveness against documented severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and symptomatic Covid-19 was estimated after the first and second vaccine doses. The cumulative incidence of each outcome in the two study groups through January 7, 2022, was estimated with the use of the Kaplan-Meier estimator, and vaccine effectiveness was calculated as 1 minus the risk ratio. Vaccine effectiveness was also estimated in age subgroups.ResultsAmong 136,127 eligible children who had been vaccinated during the study period, 94,728 were matched with unvaccinated controls. The estimated vaccine effectiveness against documented infection was 17% (95% confidence interval [CI], 7 to 25) at 14 to 27 days after the first dose and 51% (95% CI, 39 to 61) at 7 to 21 days after the second dose. The absolute risk difference between the study groups at days 7 to 21 after the second dose was 1905 events per 100,000 persons (95% CI, 1294 to 2440) for documented infection and 599 events per 100,000 persons (95% CI, 296 to 897) for symptomatic Covid-19. The estimated vaccine effectiveness against symptomatic Covid-19 was 18% (95% CI, -2 to 34) at 14 to 27 days after the first dose and 48% (95% CI, 29 to 63) at 7 to 21 days after the second dose. We observed a trend toward higher vaccine effectiveness in the youngest age group (5 or 6 years of age) than in the oldest age group (10 or 11 years of age).ConclusionsOur findings suggest that as omicron was becoming the dominant variant, two doses of the BNT162b2 messenger RNA vaccine provided moderate protection against documented SARS-CoV-2 infection and symptomatic Covid-19 in children 5 to 11 years of age. (Funded by the European Union through the VERDI project and others.).
| S-EPMC9258754 | biostudies-literature
Project description:BackgroundThe COVID-19 pandemic has evolved quickly, with different variants of concern resulting in the need to offer continued protection through booster vaccinations. The duration of enhanced protection with booster doses against severe COVID-19 is still unclear. Understanding this is critical to recommendations on the frequency of future booster doses.MethodsUtilising a Hospital Information System for COVID-19 established in Chiang Mai, Thailand, we conducted a cohort study by linking patient-level data of laboratory-confirmed COVID-19 cases to the national immunization records, during the omicron predominant period (1 February- 31 July 2022).ResultsOut of 261,103 adults with COVID-19 included in the study, there were 333 (0.13%) severe COVID-19 cases and 190 (0.07%) deaths. Protection against severe COVID-19 was highest with boosters received >14-60 days prior to positive test (93%) and persisted at >60-120 days (91%) but started to wane at >120-180 days (77%) and further at >180 days (68%). The rate of waning differed with age. Those ≥70 years showed faster waning of booster vaccine responses as compared to those aged 18-49 years, who retained good responses up to 180 days. Equivalent risk reduction against severe COVID-19 was seen with all the vaccine types used as boosters in Thailand.ConclusionsBooster doses provided high levels of protection against severe COVID-19 with omicron, up to 4 months. Repeat boosters will be required to continue protection beyond 4 months, particularly in the elderly. mRNA and viral vector vaccines can be used flexibly to improve booster coverage.
| S-EPMC10174527 | biostudies-literature
Project description:BackgroundThe short-term effectiveness of a two-dose regimen of the BioNTech/Pfizer mRNA BNT162b2 vaccine for adolescents has been demonstrated. However, little is known about the long-term effectiveness in this age group. It is known, though, that waning of vaccine-induced immunity against infection in adult populations is evident within a few months.MethodsLeveraging the centralized computerized database of Maccabi Healthcare Services (MHS), we conducted a matched case-control design for evaluating the association between time since vaccination and the incidence of infections, where two outcomes were evaluated separately: a documented SARS-CoV-2 infection (regardless of symptoms) and a symptomatic infection (COVID-19). Cases were defined as individuals aged 12 to 16 with a positive PCR test occurring between June 15 and December 8, 2021, when the Delta variant was dominant in Israel. Controls were adolescents who had not tested positive previously.ResultsWe estimated a peak vaccine effectiveness between 2 weeks and 3 months following receipt of the second dose, with 85% and 90% effectiveness against SARS-CoV-2 infection and COVID-19, respectively. However, in line with previous findings for adults, waning of vaccine effectiveness was evident in adolescents as well. Long-term protection conferred by the vaccine was reduced to 75-78% against infection and symptomatic infection, respectively, 3 to 5 months after the second dose, and waned to 58% against infection and 65% against COVID-19 after 5 months.ConclusionsLike adults, vaccine-induced protection against both SARS-CoV-2 infection and COVID-19 wanes with time, starting three months after inoculation and continuing for more than five months.
| S-EPMC8750715 | biostudies-literature