Beta SARS-CoV-2 variant and BNT162b2 vaccine effectiveness in long-term care facilities in France.
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ABSTRACT:
SUBMITTER: Lefevre B
PROVIDER: S-EPMC8457759 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:ObjectiveTo evaluate the effectiveness of the Pfizer BNT162b2 vaccine against the SARS-Cov-2 Beta variant.Study design and settingIsrael's mass vaccination program, using two doses of the Pfizer BNT162b2 vaccine, successfully curtailed the Alpha variant outbreak during winter 2020-2021, However, the virus may mutate and partially evade the immune system. To monitor this, sequencing of selected positive swab samples of interest was initiated. Comparing vaccinated with unvaccinated PCR positive persons, we estimated the odds ratio for a vaccinated case to have the Beta vs. the Alpha variant, using logistic regression, controlling for important confounders.ResultsThere were 19 cases of Beta variant (3.2%) among those vaccinated more than 14 days before the positive sample and 79 (3.4%) among the unvaccinated. The estimated odds ratio was 1.26 (95% CI: 0.65-2.46). Assuming the effectiveness against the Alpha variant to be 95%, the estimated effectiveness against the Beta variant was 94% (95% CI: 88%-98%).ConclusionDespite concerns over the Beta variant, the BNT162b2 vaccine seemed to provide substantial immunity against both the Beta and the Alpha variants. From 14 days following the second vaccine dose, the effectiveness of BNT162b2 vaccine was at most marginally affected by the Beta variant.
| S-EPMC8553421 | biostudies-literature
Project description:ObjectiveWe assessed vaccine effectiveness (VE) of BNT162b2 mRNA COVID-19 vaccine against SARS-CoV-2 acquisition among health care workers (HCWs) of long-term care facilities (LTCFs).MethodsThis prospective study, in the framework of "Senior Shield" program in Israel, included routine, weekly nasopharyngeal SARS-CoV-2 RT-PCR testing from all LTCF HCWs since July 2020. All residents and 75% of HCWs were immunized between December 2020 and January 2021. The analysis was limited to HCWs adhering to routine testing. Fully vaccinated (14+ days after second dose; n=6960) and unvaccinated HCWs (n=2202) were simultaneously followed until SARS-CoV-2 acquisition, or end of follow-up, April 11, 2021. Hazard ratios (HRs) for vaccination vs. no vaccination were calculated (Cox proportional hazards regression models, adjusting for socio-demographics and residential-area COVID-19 incidence). VE was calculated as [(1- HR)×100]. RT-PCR cycle threshold values (Cts) were compared between vaccinated and unvaccinated HCWs.ResultsAt >14 days post second dose, 40 vaccinated HCWs acquired SARS-CoV-2 (median follow-up, 66 days; cumulative incidence 0.6%) vs. 84 unvaccinated HCWs (median follow-up 43 days; cumulative incidence, 5.1%); HR=0.11 (95% CI 0.07, 0.17), unadjusted VE=89% (95% CI 83%, 93%). Adjusted VE beyond seven days and >14 days post second dose were similar. The median PCR Cts targeting ORF1ab gene among 20 vaccinated and 40 unvaccinated HCWs was 32.0 vs. 26.7, respectively, p=0.008.ConclusionsVE following two doses of BNT162b2 against SARS-CoV-2 acquisition in LTCF HCWs was high. The lower viral loads among SARS-CoV-2 positive HCWs suggests further reduction in transmission.
| S-EPMC8675294 | biostudies-literature
Project description:BackgroundSARS-CoV-2 variant Beta (B.1.351) was designated as a Variant of Concern (VoC) after becoming the dominant strain in South Africa and spreading internationally. BNT162b2 showed lower levels of neutralizing antibodies against Beta than against other strains raising concerns about effectiveness of vaccines against infections caused by Beta. We estimated BNT162b2 vaccine effectiveness (VE) against Beta infections in Israel, a country with high vaccine uptake.MethodsThe Ministry of Health (MoH) identified Beta cases through mandatory reporting of SARS-CoV-2 cases and whole genome sequencing (WGS) of specimens from vaccination-breakthrough infections, reinfections, arriving international travelers, and a selection of other infected persons. A cohort analysis was conducted of exposure events of contacts of primary Beta cases. WGS was conducted on available PCR-positive specimens collected from contacts. VE estimates with 95% confidence intervals (CIs) against confirmed and probable Beta infections were determined by comparing infection risk between unvaccinated and fully-vaccinated (≥7 days after the second dose) contacts, and between unvaccinated and partially-vaccinated (<7 days after the second dose) contacts.FindingsMoH identified 310 Beta cases through Jun 27, 2021. During the study period (Dec 11, 2020 - Mar 25, 2021), 164 non-institutionalized primary Beta cases, with 552 contacts aged ≥16 years, were identified. 343/552 (62%) contacts were interviewed and tested. 71/343 (21%) contacts were PCR-positive. WGS was performed on 7/71 (10%) PCR-positive specimens; all were Beta. Among SARS-CoV-2-infected contacts, 48/71 (68%) were symptomatic, 10/71 (14%) hospitalized, and 2/71 (3%) died. Fully-vaccinated VE against confirmed or probable Beta infections was 72% (95% CI -5 - 97%; p=0·04) and against symptomatic confirmed or probable Beta infections was 100% (95% CI 19 - 100%; p=0·01). There was no evidence of protection in partially-vaccinated contacts.InterpretationIn a prospective observational study, two doses of BNT162b2 were effective against confirmed and probable Beta infections. Through the end of June 2021, introductions of Beta did not interrupt control of the pandemic in Israel.FundingIsrael Ministry of Health and Pfizer.
| S-EPMC8628463 | biostudies-literature
Project description: Not available
| S-EPMC8552532 | biostudies-literature
Project description:As the SARS-CoV-2 pandemic continues to rage worldwide, the emergence of numerous variants of concern (VOC) represents a challenge for the vaccinal protective efficacy and the reliability of commercially available high-throughput immunoassays. Our study demonstrates the administration of two doses of the BNT162b2 vaccine that elicited a robust SARS-CoV-2-specific immune response which was assessed up to 3 months after full vaccination in a cohort of 37 health care workers (HCWs). SARS-CoV-2-specific antibody response, evaluated by four commercially available chemiluminescence immunoassays (CLIA), was qualitatively consistent with the results provided by the gold-standard in vitro neutralization assay (NTA). However, we could not observe a correlation between the quantity of the antibody detected by CLIA assays and their neutralizing activity tested by NTA. Almost all subjects developed a SARS-CoV-2-specific T-cell response. Moreover, vaccinated HCWs developed a similar protective neutralizing antibodies response against the EU (B.1), Alpha (B.1.1.7), Gamma (P.1), and Eta (B.1.525) SARS-CoV-2 variants, while Beta (B.1.351) and Delta (B.1.617.2) strains displayed a consistent partial immune evasion. These results underline the importance of a solid vaccine-elicited immune response and a robust antibody titre. We believe that these relevant results should be taken into consideration in the definition of future vaccinal strategies.
| S-EPMC8648019 | biostudies-literature
Project description:BackgroundThe SARS-CoV-2 Omicron variant, designated as a Variant of Concern(VOC) by the World Health Organization, carries numerous spike mutations which have are known to evade neutralizing antibodies elicited by COVID-19 vaccines. A deeper understanding of the susceptibility of Omicron variant to vaccine-induced neutralizing antibodies is urgently needed for risk assessment.MethodsOmicron variant strains HKU691 and HKU344-R346K were isolated from patients using TMPRSS2-overexpressing VeroE6 cells. Whole genome sequence was determined using nanopore sequencing. Neutralization susceptibility of ancestral lineage A virus and the Omicron, Delta and Beta variants to sera from 25 BNT162b2 and 25 Coronavac vaccine recipients was determined using a live virus microneutralization assay.ResultsThe Omicron variant strain HKU344-R346K has an additional spike R346K mutation, which is present in 8.5% of strains deposited in GISAID database. Only 20% and 24% of BNT162b2 recipients had detectable neutralizing antibody against the Omicron variant HKU691 and HKU344-R346K, respectively, while none of the Coronavac recipients had detectable neutralizing antibody titer against either Omicron isolate. For BNT162b2 recipients, the geometric mean neutralization antibody titers(GMT) of the Omicron variant isolates(5.43 and 6.42) were 35.7-39.9-fold lower than that of the ancestral virus(229.4), and the GMT of both Omicron variant isolates were significantly lower than those of the Beta and Delta variants. There was no significant difference in the GMT between HKU691 and HKU344-R346K.ConclusionsOmicron variant escapes neutralizing antibodies elicited by BNT162b2 or Coronavac. The additional R346K mutation did not affect the neutralization susceptibility. Our data suggest that the Omicron variant may be associated with lower COVID-19 vaccine effectiveness.
| S-EPMC8754807 | biostudies-literature
Project description:BackgroundThe effectiveness of SARS-CoV-2 vaccines in older adults living in long-term care facilities is uncertain. We investigated the protective effect of the first dose of the Oxford-AstraZeneca non-replicating viral-vectored vaccine (ChAdOx1 nCoV-19; AZD1222) and the Pfizer-BioNTech mRNA-based vaccine (BNT162b2) in residents of long-term care facilities in terms of PCR-confirmed SARS-CoV-2 infection over time since vaccination.MethodsThe VIVALDI study is a prospective cohort study that commenced recruitment on June 11, 2020, to investigate SARS-CoV-2 transmission, infection outcomes, and immunity in residents and staff in long-term care facilities in England that provide residential or nursing care for adults aged 65 years and older. In this cohort study, we included long-term care facility residents undergoing routine asymptomatic SARS-CoV-2 testing between Dec 8, 2020 (the date the vaccine was first deployed in a long-term care facility), and March 15, 2021, using national testing data linked within the COVID-19 Datastore. Using Cox proportional hazards regression, we estimated the relative hazard of PCR-positive infection at 0-6 days, 7-13 days, 14-20 days, 21-27 days, 28-34 days, 35-48 days, and 49 days and beyond after vaccination, comparing unvaccinated and vaccinated person-time from the same cohort of residents, adjusting for age, sex, previous infection, local SARS-CoV-2 incidence, long-term care facility bed capacity, and clustering by long-term care facility. We also compared mean PCR cycle threshold (Ct) values for positive swabs obtained before and after vaccination. The study is registered with ISRCTN, number 14447421.Findings10 412 care home residents aged 65 years and older from 310 LTCFs were included in this analysis. The median participant age was 86 years (IQR 80-91), 7247 (69·6%) of 10 412 residents were female, and 1155 residents (11·1%) had evidence of previous SARS-CoV-2 infection. 9160 (88·0%) residents received at least one vaccine dose, of whom 6138 (67·0%) received ChAdOx1 and 3022 (33·0%) received BNT162b2. Between Dec 8, 2020, and March 15, 2021, there were 36 352 PCR results in 670 628 person-days, and 1335 PCR-positive infections (713 in unvaccinated residents and 612 in vaccinated residents) were included. Adjusted hazard ratios (HRs) for PCR-positive infection relative to unvaccinated residents declined from 28 days after the first vaccine dose to 0·44 (95% CI 0·24-0·81) at 28-34 days and 0·38 (0·19-0·77) at 35-48 days. Similar effect sizes were seen for ChAdOx1 (adjusted HR 0·32, 95% CI 0·15-0·66) and BNT162b2 (0·35, 0·17-0·71) vaccines at 35-48 days. Mean PCR Ct values were higher for infections that occurred at least 28 days after vaccination than for those occurring before vaccination (31·3 [SD 8·7] in 107 PCR-positive tests vs 26·6 [6·6] in 552 PCR-positive tests; p<0·0001).InterpretationSingle-dose vaccination with BNT162b2 and ChAdOx1 vaccines provides substantial protection against infection in older adults from 4-7 weeks after vaccination and might reduce SARS-CoV-2 transmission. However, the risk of infection is not eliminated, highlighting the ongoing need for non-pharmaceutical interventions to prevent transmission in long-term care facilities.FundingUK Government Department of Health and Social Care.
| S-EPMC8221738 | biostudies-literature
Project description: Not available
| S-EPMC8757569 | biostudies-literature
Project description: Not available
| EMPIAR-11181 | biostudies-other
Project description: Not available
| S-EPMC8008745 | biostudies-literature