Dataset Information

Protective effect conferred by prior infection and vaccination on COVID-19 in a healthcare worker cohort in South India.

ABSTRACT:

Background

The emergence of newer variants with the immune escape potential raises concerns about breakthroughs and re-infections resulting in future waves of infection. We examined the protective effect of prior COVID-19 disease and vaccination on infection rates among a cohort of healthcare workers (HCW) in South India during the second wave driven mainly by the delta variant.

Methods and findings

Symptomatic HCWs were routinely tested by RT-PCR as per institutional policy. Vaccination was offered to all HCWs in late January, and the details were documented. We set up a non-concurrent cohort to document infection rates and estimated protective efficacy of prior infection and vaccination between 16th Apr to 31st May 2021, using a Cox proportional hazards model with time-varying covariates adjusting for daily incidence. Between June 2020 and May 2021, 2735 (23.9%) of 11,405 HCWs were infected, with 1412, including 32 re-infections, reported during the second wave. 6863 HCWs received two doses of vaccine and 1905 one dose. The protective efficacy of prior infection against symptomatic infection was 86.0% (95% CI 76.7%-91.6%). Vaccination combined with prior infection provided 91.1% (95% CI 84.1%-94.9%) efficacy. In the absence of prior infection, vaccine efficacy against symptomatic infection during the second wave was 31.8% (95% CI 23.5%- 39.1%).

Conclusions

Prior infection provided substantial protection against symptomatic re-infection and severe disease during a delta variant driven second wave in a cohort of health care workers.

SUBMITTER: Murugesan M

PROVIDER: S-EPMC9122209 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature

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Publications

Protective effect conferred by prior infection and vaccination on COVID-19 in a healthcare worker cohort in South India.

Murugesan Malathi M Mathews Prasad P Paul Hema H Karthik Rajiv R Mammen Joy John JJ Rupali Priscilla P

PloS one 20220520 5

<h4>Background</h4>The emergence of newer variants with the immune escape potential raises concerns about breakthroughs and re-infections resulting in future waves of infection. We examined the protective effect of prior COVID-19 disease and vaccination on infection rates among a cohort of healthcare workers (HCW) in South India during the second wave driven mainly by the delta variant.<h4>Methods and findings</h4>Symptomatic HCWs were routinely tested by RT-PCR as per institutional policy. Vacc ...[more]

PMID: 35594270

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Project description:BackgroundThe protection of fourth dose mRNA vaccination against SARS-CoV-2 is relevant to current global policy decisions regarding ongoing booster roll-out. We aimed to estimate the effect of fourth dose vaccination, prior infection, and duration of PCR positivity in a highly-vaccinated and largely prior-COVID-19 infected cohort of UK healthcare workers.MethodsParticipants underwent fortnightly PCR and regular antibody testing for SARS-CoV-2 and completed symptoms questionnaires. A multi-state model was used to estimate vaccine effectiveness (VE) against infection from a fourth dose compared to a waned third dose, with protection from prior infection and duration of PCR positivity jointly estimated.Findings1298 infections were detected among 9560 individuals under active follow-up between September 2022 and March 2023. Compared to a waned third dose, fourth dose VE was 13.1% (95% CI 0.9 to 23.8) overall; 24.0% (95% CI 8.5 to 36.8) in the first 2 months post-vaccination, reducing to 10.3% (95% CI -11.4 to 27.8) and 1.7% (95% CI -17.0 to 17.4) at 2-4 and 4-6 months, respectively. Relative to an infection >2 years ago and controlling for vaccination, 63.6% (95% CI 46.9 to 75.0) and 29.1% (95% CI 3.8 to 43.1) greater protection against infection was estimated for an infection within the past 0-6, and 6-12 months, respectively. A fourth dose was associated with greater protection against asymptomatic infection than symptomatic infection, whilst prior infection independently provided more protection against symptomatic infection, particularly if the infection had occurred within the previous 6 months. Duration of PCR positivity was significantly lower for asymptomatic compared to symptomatic infection.InterpretationDespite rapid waning of protection, vaccine boosters remain an important tool in responding to the dynamic COVID-19 landscape; boosting population immunity in advance of periods of anticipated pressure, such as surging infection rates or emerging variants of concern.FundingUK Health Security Agency, Medical Research Council, NIHR HPRU Oxford, Bristol, and others.

Project description:BackgroundThe rapid development and deployment of effective COVID-19 vaccines have been critical to halt the spread of the pandemic. India started vaccinating children in early 2022, however, vaccine uptake has been suboptimal.MethodsBetween September and November 2022, we conducted an online survey that was disseminated to eligible participants via email, text messages and social media platforms across India. The survey aimed to gather the perspectives of Indian healthcare providers regarding key factors related to the rollout of paediatric COVID-19 vaccines. Descriptive statistics were used to analyse participant demographics and responses on knowledge about paediatric COVID-19 vaccines, perceived risks and benefits, and vaccine rollout strategies.ResultsThe survey yielded 805 respondents from 23 Indian states; 63.5% were men, 97.3% were paediatricians, median age was 44 years (IQR 25-81). Eighty-one per cent and 65.2% respondents had heard about the most common paediatric COVID-19 vaccines in India, Covaxin and Corbevax, but only 52.9%, 53.7% and 62.1% felt adequately informed about their safety, efficacy and vaccination schedules, respectively. Thirty per cent of respondents were unaware of vaccination guidelines. Eighty-five per cent of respondents felt that vaccines would reduce the incidence of severe disease, hospitalisation and deaths, and 60.6% felt children with comorbidities should be prioritised for vaccination. Perceived supply side barriers included lack of enforcement of guidelines (45.2%) and adverse effects following immunisation monitoring systems (37.6%), and on the demand side, parental vaccine hesitancy (64.4%). Eighty-one per cent believed that school-based vaccination strategies would be highly effective in increasing uptake.ConclusionsMost respondents were in support of the COVID-19 paediatric vaccination, although just over half did not feel adequately informed. Concerns about vaccine hesitancy among caregivers were the leading reported barrier. Targeted interventions are needed to provide adequate knowledge support to healthcare providers and evidence-based public health messaging to reduce vaccine hesitancy among caregivers.

Dataset Information

Protective effect conferred by prior infection and vaccination on COVID-19 in a healthcare worker cohort in South India.

Background

Methods and findings

Conclusions

Publications

Protective effect conferred by prior infection and vaccination on COVID-19 in a healthcare worker cohort in South India.

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