Effectiveness of public health measures in reducing COVID-19 incidence, transmission, and mortality: systematic review and meta-analysis
A variety of containment and mitigation strategies have been adopted to adequately respond to COVID-19, with the intention of deferring major surges of patients in hospitals and protecting the most vulnerable people from infection, including elderly people and those with comorbidities. Strategies to achieve these goals are diverse, commonly based on national risk assessments that include estimation of numbers of patients requiring hospital admission and availability of hospital beds and ventilation support.
Globally, vaccination programmes have proved to be safe and effective and save lives.Yet most vaccines do not confer 100% protection, and it is not known how vaccines will prevent future transmission of SARS-CoV-2, given emerging variants. The proportion of the population that must be vaccinated against COVID-19 to reach herd immunity depends greatly on current and future variants. This vaccination threshold varies according to the country and population’s response, types of vaccines, groups prioritised for vaccination, and viral mutations, among other factors. Until herd immunity to COVID-19 is reached, regardless of the already proven high vaccination rates, public health preventive strategies are likely to remain as first choice measures in disease prevention, particularly in places with a low uptake of COVID-19 vaccination. Measures such as lockdown (local and national variant), physical distancing, mandatory use of face masks, and hand hygiene have been implemented as primary preventive strategies to curb the COVID-19 pandemic.