Handwashing, mask wearing, and physical distancing should continue alongside vaccinations because they help to reduce the incidence of COVID-19, experts say today.
However, writing in the latest edition of The BMJ, the researchers say further assessment is needed to see what potential negative effects there would be on the general population if more stringent measures, such as lockdowns and closures of borders, schools and workplaces were reintroduced.
Previous reviews have not been robust enough to allow researchers to make firm conclusions about the effectiveness of public health interventions in reducing COVID-19 incidence rates.
So, researchers at Monash University, Australia, reviewed 35 studies that evaluated individual public health measures and 37 assessed multiple public health measures – 72 in total – in reducing the incidence of COVID-19, SARS-CoV-2 transmission and COVID-19 mortality.
Out of the 35 studies that assessed individual measures, 34 were observational and one was a randomised controlled trial.
Results from eight were analysed in detail, which indicated mask wearing resulted in a statistically significant 53% reduction in the incidence of COVID-19 with mask wearing, while physical distancing led to a 25% reduction.
Although handwashing indicated a substantial 53% reduction in COVID-19 incidence, when it was adjusted for the small number of studies, it was not found to be statistically significant.
The researchers were unable to complete detailed analysis for measures such as quarantine and isolation, universal lockdowns, and closures of borders, schools, and workplaces, because the studies used different designs, outcome measures and quality.
They add that while high quality evidence on the effectiveness of public health measures is still limited, their comprehensive search strategy to identify and select studies for review minimised bias, which suggests the results are robust.
Lead author Dr Stella Talic said further research is also needed to assess the effectiveness of public health measures after adequate vaccination coverage.
Talic S, Shah S, Wild H et al. Effectiveness of public health measures in reducing the incidence of COVID-19, SARS-CoV-2 transmission, and COVID-19 mortality: systematic review and meta-analysis. BMJ 18 November 2021.
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