Background

BBV152 is a whole-virion inactivated SARS-CoV-2 vaccine that has been deployed in India. The results of the phase 3 trial have shown clinical efficacy of BBV152. We aimed to evaluate the effectiveness of BBV152 against symptomatic RT-PCR-confirmed SARS-CoV-2 infection.

Methods

We conducted a test-negative, case-control study among employees of the All India Institute of Medical Sciences (a tertiary care hospital in New Delhi, India), who had symptoms suggestive of COVID-19 and had an RT-PCR test for SARS-CoV-2 during the peak of the second wave of the COVID-19 pandemic in India between April 15 and May 15, 2021. Cases (test-positives) and controls (test-negatives) were matched (1:1) on the basis of age and gender. The odds of vaccination with BBV152 were compared between cases and controls and adjusted for level of occupational exposure (to COVID-19), previous SARS-CoV-2 infection, and calendar time, using conditional logistic regression. The primary outcome was effectiveness of two doses of BBV152 (with the second dose received at least 14 days before testing) in reducing the odds of symptomatic RT-PCR-confirmed SARS-CoV-2 infection, expressed as (1 – odds ratio) × 100%.

Findings

Between April 15 and May 15, 2021, 3732 individuals had an RT-PCR test. Of these, 2714 symptomatic employees had data on vaccination status, and 1068 matched case-control pairs were available for analysis. The adjusted effectiveness of BBV152 against symptomatic COVID-19 after two doses administered at least 14 days before testing was 50% (95% CI 33–62; p<0·0001). The adjusted effectiveness of two doses administered at least 28 days before testing was 46% (95% CI 22–62) and administered at least 42 days before testing was 57% (21–76). After excluding participants with previous SARS-CoV-2 infections, the adjusted effectiveness of two doses administered at least 14 days before testing was 47% (95% CI 29–61).

Interpretation

This study shows the effectiveness of two doses of BBV152 against symptomatic COVID-19 in the context of a huge surge in cases, presumably dominated by the potentially immune-evasive delta (B.1.617.2) variant of SARS-CoV-2. Our findings support the ongoing roll-out of this vaccine to help control the spread of SARS-CoV-2, while continuing the emphasis on adherence to non-pharmacological measures.

Funding

None.

Translation

For the Hindi translation of the abstract see Supplementary Materials section.

中文翻译：

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印度灭活病毒 SARS-CoV-2 疫苗 BBV152 的有效性：一项检测阴性的病例对照研究

背景

BBV152 是一种全病毒粒子灭活的 SARS-CoV-2 疫苗，已在印度部署。3期试验结果显示了BBV152的临床疗效。我们旨在评估 BBV152 对症状性 RT-PCR 确认的 SARS-CoV-2 感染的有效性。

方法

我们在全印度医学科学研究所（印度新德里的一家三级护理医院）的员工中进行了一项检测阴性的病例对照研究，他们出现了提示 COVID-19 的症状并接受了 SARS 的 RT-PCR 检测-CoV-2 在 2021 年 4 月 15 日至 5 月 15 日期间在印度发生的第二波 COVID-19 大流行高峰期间。病例（测试阳性）和对照（测试阴性）在年龄和性别的基础。在病例和对照组之间比较了 BBV152 疫苗接种的几率，并使用条件逻辑回归根据职业暴露水平（对 COVID-19）、先前的 SARS-CoV-2 感染和日历时间进行了调整。

发现

在 2021 年 4 月 15 日至 5 月 15 日期间，3732 人进行了 RT-PCR 测试。其中，2714 名有症状的员工有疫苗接种状态数据，1068 对匹配的病例-对照对可用于分析。在测试前至少 14 天给予两次剂量后，BBV152 对症状性 COVID-19 的调整有效性为 50%（95% CI 33–62；p<0·0001）。测试前至少 28 天给药的两剂调整后的有效性为 46% (95% CI 22-62)，测试前至少 42 天给药的调整后有效性为 57% (21-76)。在排除既往感染过 SARS-CoV-2 的参与者后，在测试前至少 14 天给予两次剂量的调整后有效性为 47% (95% CI 29-61)。

解释

这项研究表明，在病例激增的情况下，两剂 BBV152 对有症状的 COVID-19 的有效性，可能由 SARS-CoV-2 的潜在免疫规避 delta (B.1.617.2) 变体主导。我们的研究结果支持正在推出这种疫苗以帮助控制 SARS-CoV-2 的传播，同时继续强调坚持非药物措施。

资金

没有。

翻译

对于摘要的印地语翻译，请参阅补充材料部分。