Effective mitigation: a systematic review
Effective public health measures to mitigate the spread of COVID-19: a systematic review
We systematically searched PubMed, Science Direct and MedRxiv for relevant articles published in English up to March 16, 2021. We included quasi experimental studies, clinical trials, cohort studies, longitudinal studies, case-control studies and interrupted time series. [We found] 13,497 studies [and only] 18 articles were included. Travel restrictions, borders measures, quarantine of travellers arriving from affected countries, city lockdown, restrictions of mass gathering, isolation and quarantine of confirmed cases and close contacts, social distancing measures, compulsory mask wearing, contact tracing and testing, school closures and personal protective equipment use among health workers were effective in mitigating the spread of COVID-19.
Differential impact of non-pharmaceutical public health interventions on COVID-19 epidemics in the United States
The effective reproduction number (Rt) of COVID-19 epidemic for 50 states in the US was estimated. Different NPIs were found to have led to different levels of reduction in Rt. Stay-at-home contributed approximately 51% (95% CI 46–57%), wearing (face) masks 29% (15–42%), gathering ban (more than 10 people) 19% (14–24%), non-essential business closure 16% (10–21%), declaration of emergency 13% (8–17%), interstate travel restriction 11% (5–16%), school closure 10% (7–14%), initial business closure 10% (6–14%), and gathering ban (more than 50 people) 7% (2–11%). NPIs played critical roles on epidemic control in the US in the past several months.
Evaluating different national strategies to contain the COVID-19 pandemic before mass vaccination
In Vietnam, Thailand, Bhutan, Taiwan, China, Cambodia, Singapore, and New Zealand, at least 100 times fewer people died from COVID-19 in comparison to many western countries. The argument of many western countries that avoided the proactive approach and the introduction of measures was that in this way they would manage to save their economies from the “unimaginable downturns” that would follow the enforcement of stringent anti-epidemic measures. [Still, the first group of countries] had a notably small number of deaths, and they also managed to achieve economic growth. In the cases where economic growth wasn't achieved, only a very slight decline was recorded. The initial dilemma about whether we should work to save human lives or preserve the economy was a false one.
All five COVID-19 outbreaks during epidemic period of 2020/2021 in China were instigated by asymptomatic or pre-symptomatic individuals
In this study, all five COVID-19 outbreaks reported in China since October 2020 were analyzed. The Kashgar outbreak in Xinjiang province came into light for the first time on October 22, 2020. However, it was initiated before October 11, 2020, by a local asymptomatic import and export worker, who was infected at the working place. Subsequently, his wife caught the infection, which led to 430 more infections reported in the outbreak. The Beijing outbreak with 41 cases was noticed for the first time on December 22, 2020. However, our analysis revealed that it was initiated by an asymptomatic individual from Indonesia on December 10, 2020. The Shenyang outbreak, with 38 cases, noticed for the first time on December 23, 2020, was initiated by a pre-symptomatic individual from South Korea on December 13, 2020. The asymptomatic or pre-symptomatic individuals during the asymptomatic period were unsuspectingly infected by SARS-CoV-2, and unintentionally transmitted the virus to a large number of people. These findings suggest that early detection of asymptomatic or pre-symptomatic individuals is of critical importance in preventing future outbreaks or epidemics.
Face masks effectively limit the probability of SARS-CoV-2 transmission
We find that most environments and contacts are under conditions of low virus abundance (virus-limited) where surgical masks are effective at preventing virus spread. More advanced masks and other protective equipment are required in potentially virus-rich indoor environments including medical centers and hospitals. Masks are particularly effective in combination with other preventive measures like ventilation and distancing.