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Article analysis:

The article is a systematic review and meta-regression that assesses the duration of protection of COVID-19 vaccines against various clinical outcomes. The authors conducted a systematic review of preprint and peer-reviewed published article databases from June 17, 2021, to Dec 2, 2021. The risk of bias was low for three studies, moderate for eight studies, and serious for seven studies. The results showed that on average, vaccine efficacy or effectiveness against SARS-CoV-2 infection decreased from 1 month to 6 months after full vaccination by 21·0 percentage points among people of all ages and 20·7 percentage points among older people.

The trustworthiness and reliability of this article is generally good as it is based on a systematic review and meta-regression which are considered reliable methods in research. However, there are some potential biases that should be noted such as the fact that only preprint and peer reviewed published articles were included in the search which may have excluded some relevant studies; also, the risk of bias was low for three studies, moderate for eight studies, and serious for seven studies which could affect the accuracy of the results obtained from these studies. Additionally, there is no mention in the article about possible risks associated with taking the vaccine which should be noted when discussing its effectiveness. Furthermore, there is no discussion about unexplored counterarguments or missing points of consideration which could provide more insight into the findings presented in this article. Finally, there is no mention about promotional content or partiality which could influence readers’ interpretation of the results presented in this article.