Effectiveness of SARS‐CoV‐2 inactivated vaccine and the correlation to neutralizing antibodies: a test‐negative case‐control study

alexandrossfakianakis shared this article with you from Inoreader Effectiveness of SARS‐CoV‐2 inactivated vaccine and the correlation to neutralizing antibodies: a test‐negative case‐control study via Journal of Medical Virology Abstract Purpose SARS-CoV-2 breakthrough infection in highly vaccinated populations raises study on the effectiveness for inactivated vaccine, including effectiveness of the vaccine dose, the continuance of effectiveness, the effectiveness against severe/critical COVID-19 and against secondary attacks. Methods A population of 10 870 close contacts were investigated in a Delta variant's epidemic. The effectiveness of vaccination was estimated in a test-negative case-control study. And serum was used to detect neutralizing antibodies to explore their correlation to effectiveness. The vaccine effectiveness (VE) values were estimated for populations aged 12 or older. Results The overall adjusted VE was 56.2%, and 2-dose vaccine was more effective than 1-dose (56.7% vs. 43.8%). And the population that got the second dose vaccine within 2 months showed higher VE than the population vaccinated for longer than 2 months (61.5% vs. 52.3%). Among the population who vaccinated 2 doses or within 2 months, a higher level of neutralizing antibodies was observed. For infected cases, vaccinated populations showed lower rates of transmission (2.63% vs. 4.36%). And those vaccinated cases, who were not found causing transmission, had a higher level of antibodies. Conclusions The study provided a full view of the effectiveness of inactivated vaccines in a real-world setting. The time-related vaccine effectiveness against infection and lower transmission of breakthrough vaccinated cases were observed, which may indicate that a necessity of a booster vaccine to maintain the effectiveness and high level of neutralizing antibody. This article is protected by copyright. All rights reserved. View on Web

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