The mask issue was certainly one of the most controversial of the Covid-19 pandemic and beyond. Do masks do anything or not? The researchers have now presented a new overall study. The result is very clear: yes.
It was and is the subject of heated debates: the question of whether masks can prevent the spread of coronavirus – or not. A team led by New York scientist Shama Cash-Goldwasser has published an overall new study. Researchers analyzed several high-quality observational studies. The result: Face masks can limit the spread of the coronavirus. “Available data supports the use of face masks in the population to reduce transmission of SARS-CoV-2,” the investigators write.
According to the study, these findings should serve as a basis for future combating epidemics and pandemics caused by respiratory viruses. “The effectiveness of the measures will depend, at least in part, on the use of lessons learned from the Covid-19 pandemic. High-quality masks that are made widely available could also play an important role in containing pathogens in future pandemics,” the researchers wrote. .
Available data supports the use of face masks in the community to reduce transmission of SARS-CoV-2
Shama Cash-Goldwasser | Lead author of new overview study
Masks examined on planes, schools and at home
Researchers analyzed several observational studies on the effects of masks on airplanes, schools, and in household and community contacts. They said an outbreak of Covid-19 on the aircraft carrier USS Theodore Roosevelt early in the pandemic, before crew members could develop immunity, was instructive. “More than 80% of those who said they did not wear a mask were infected,” the scientists write. “In contrast, those who said they wore a mask were 30% less likely to be infected.” As people on ships often live together in confined, poorly ventilated spaces for long periods of time, there is generally a high risk of respiratory disease outbreaks.
Mask type and fit affect transmission
However, scientists admit: even the best masks do not offer complete protection. Effectiveness depends on many factors. “The benefits of wearing masks are limited if masks are not used in all settings where transmission occurs.” For example, healthcare workers who consistently wear masks when working with patients can still become infected – if the mask is removed – during breaks or during conversations with colleagues. Additionally, both mask type and fit are crucial to effectiveness.
Conceptual mask proven in the laboratory
According to the study, laboratory studies have proven that masks can fundamentally reduce infectious respiratory droplets and aerosols. Human breathing was simulated and the use of fabric masks, surgical masks and N95 respirators was tested using various techniques. “The reduction in the spread of droplets and aerosols is greater when both the source and the exposed person are masked,” the researchers write. According to the study, N95 respirators have the highest filter performance. They have been proven to provide the best protection against coronavirus transmission.
The overall study “Masks during pandemics caused by respiratory pathogens – evidence and implications for action” looked at several individual so-called observational studies. In these studies, conditions are not influenced by researchers. In contrast, randomized controlled trials (RCTs) work with an experimental group and a control group that uses placebos.
However, in their overall analysis, researchers led by Shama Cash-Goldwasser intentionally focused “only” on observational studies published so far. “Randomized controlled trials and meta-analyses can have significant limitations and should not constitute the sole or even the primary basis for public health decisions,” the investigators wrote. “Such studies are by no means the gold standard for proving the effectiveness of all measures.” On the contrary: Disagreement over whether face masks reduce the spread of the coronavirus has increased due to the focus on randomized trials. Unfortunately, these are “limited in number, scope and statistical significance,” the researchers explain their focus.
What are observational studies?In an observational study, a group of people are observed over a period of time without the researchers directing or controlling the conditions. This also includes many studies that look at the real-world effects of certain medications or measures. A problem is often that external influences, so-called intervening factors, can never be excluded with 100% certainty. Many experts, for example from the Health Foundation, believe that randomized and controlled studies provide greater evidence. On the one hand, influencing factors are carefully controlled and, on the other hand, there are comparison groups. Such randomized, controlled studies are not always possible. Among other things, there are ethical considerations: for example, it is considered unacceptable to intentionally expose study participants to cigarette smoke to investigate the effect on the development of cancer.
What do the most recent studies say?
It was only in June this year that the study “Physical Interventions to Stop or Reduce the Spread of Respiratory Viruses” by the renowned Cochrane research network caused controversy. It states, among other things: “The use of masks by the population is likely to have little or no influence on the occurrence of illnesses similar to influenza or COVID-19, compared to not wearing masks.”
Opponents of masks have interpreted this statement to mean that masks do not protect against coronavirus infection. The Cochrane research network immediately commented: “Most studies are older and relate to the transmission of flu and other cold viruses; studies on the corona pandemic remain in the minority.” And in the study itself, the researchers pointed out: “The risk of bias in RCTs and pooled RCTs was generally high or unclear.”
Most studies are older and relate to the transmission of flu and other cold viruses; studies on the corona pandemic remain in the minority
Cochrane Network statement on their study in June 2023
The fight against pandemics must be multifaceted
Despite all the reports of mask-wearing success, the researchers in the current New York study make it clear: “In every pandemic or epidemic, mask-wearing is just one of several measures.” The most effective strategies involved “a multifaceted response, including vaccination (when available), isolation of infectious individuals, and protection through risk reduction – including the use of high-quality masks.”
The Japanese are the ones who wear masks the most
The Japanese seem to have a better understanding that masks help contain disease. Because, as an Osaka University study reveals, Japan had the highest rates of mask use in the world during the Covid pandemic. And even after the pandemic, the Japanese are not abandoning their beloved masks. “Our online survey shows that 59% of Japanese participants still wear masks even after the downgrading of the legal status of COVID-19,” explains Michio Murakami, author of the study published in the International Journal of Disaster Risk Reduction. However, Murakami also writes that even before the pandemic, 67% of Japanese people wore a mask. 291 people aged 20 to 69 participated in the survey in April and June 2023.
Masks as a means of reducing fears
But what motivates the Japanese to wear masks, even without a medical need? In his study, Murakami found that Japanese people also wear masks for socio-psychological reasons. “A common reason is what we call ‘relief.’ Wearing a mask reduces anxiety for many people”, explains Murakami. A second reason is the norm. “People wear masks because they see other people wearing masks.”