Keeping masks even with high Covid vaccination can save lives, new study points out

Continuing to wear masks for some time, even after high levels of vaccination against Covid-19 are reached, is a measure that would help save tens of thousands of lives and prevent hundreds of thousands of hospitalizations, says a new study in the US. .

The calculations were based on the American population, but could be applied to many other countries, write the authors of the research, which has just appeared in the specialized journal Lancet Public Health.

“Our findings underscore the idea that vaccination alone is not enough to control the pandemic, and that protective measures that function as different overlapping layers are necessary to limit economic impacts and deaths,” said lead study author Bruce Y. Lee of the City University of New York in an official statement.

At the same time, “it’s like a light at the end of the tunnel,” says Peter Hotez, an expert in tropical medicine and vaccine development at the Baylor College of Medicine in Texas.

“Our work suggests that mask use does not have to go on forever, but it does indicate that it is still an important tool to slow the spread of Covid-19 as we enter the next phase of the pandemic.”

The research published by Lee, Hotez and other colleagues is a mathematical modeling of the interaction between different factors that influence disease transmission today, such as people’s susceptibility to the virus, the percentage of the population already vaccinated, the effectiveness of vaccines, the use of of masks and their effectiveness (which varies considerably between fabric, surgical and so-called PFF2 models, which are more recommended).

The team also took into account the costs of each parameter for the population and for the government, as well as different vaccination targets, between 70% and 90% of the inhabitants vaccinated by the middle of 2022.

In all simulated scenarios, the models indicate that it is worthwhile to maintain the use of masks between two and ten weeks after the vaccination target is reached. The longer it takes to reach this goal, the more positive the impact of using masks.

If, for example, the US has vaccinated 80% of its population by July 1, 2022, continued use of face protection by then could save 23,200 lives.

At a faster pace and greater vaccination coverage (May 1 and 90% of the population vaccinated), masks would still prevent 136,700 hospitalizations and 16,000 deaths. From an economic point of view, face protection would help to save investments in health even if it costs the equivalent of R$ 6.50 per day per person.

The calculations also indicate that the positive effects of masks are even clearer precisely in the scenarios that the world has faced in recent months: the emergence of more transmissible variants of the coronavirus (such as delta and omicron), against which vaccines no longer have. the original effectiveness (this is clearly the case with the omni).

The same goes for situations in which vaccine or natural immunity (produced when people recover from infection with the virus) decreases over time, a factor already known to be important in the case of Covid-19.

The publication of the findings comes at a time when different regions of the US have been easing or ending the use of masks, even indoors, a process that is beginning to accelerate in Brazil. Rio de Janeiro, for example, abolished the mandatory use of face protection in all environments.

The calculations made by the researchers indicate that, in many regions of the country, this type of measure is still premature in closed environments, the most dangerous in terms of the ease of transmission of the disease.