Are anti-mutant virus masks useful? Latest large-scale trial of 300,000 people: infection rate reduced by at least 30%
Recently, cases have been confirmed in Taiwan of the Indian Delta virus strain. The Epidemic Command Center also announced on September 11 that the genetic sequencing results of 27 confirmed cases in Banqiao Kindergarten and community-related cases “are all Delta viruses.” Taiwan, which was easily “liberated” from alert level 3, has once again been cast into a shadow.
In fact, in order to subdue the epidemic as soon as possible, in addition to relying on increasing vaccination penetration and achieving “herd immunity”, the level of people’s awareness of epidemic prevention will also determine the direction of the epidemic.
Can wearing a mask implement epidemic prevention? Large-scale study in Bangladesh hopes for answers
Taiwan’s success in epidemic prevention last year was attributed by many to the people’s generally good awareness of epidemic prevention and the nationwide cooperation in “wearing masks” to avoid the risk of community transmission. However, although scientists believe that “wearing masks” can indeed block and reduce the spread of the virus, There is no data to quantify or prove how helpful wearing a mask is in containing the virus. Now, research teams from Bangladesh and the United States are conducting large-scale studies in 600 villages in Bangladesh to explore the effectiveness of mask use. According to the Washington Post, the study involved more than 342,000 adults and was the largest randomized trial of mask use ever conducted.
Foreign reports pointed out that since March 2020, the Bangladesh government has made it compulsory for people to wear masks, but the penetration rate is still very limited. This experiment started in November 2020 and ended in April 2021, lasting about half a year. The research team divided the subjects into “intervention group” and “control group”; in the intervention group, approximately 178,800 subjects received free masks, and under the guidance of the research team, they knew the relevant information about wearing masks. Importance and related messages, health and education-related epidemic prevention awareness; the research team also tried to let opinion leaders in the community become people’s role models, and continued to communicate with face-to-face mask wearing reminders during an eight-week period.
The 164,000 subjects in the control group did not receive free masks, nor did they receive reminders and guidance from researchers. The researchers then placed observers in the communities where the subjects lived, and regularly tracked how many people were wearing masks correctly in mosques, markets, villages, tea stalls, main roads, etc. every week. Maintain social distance" and other epidemic prevention behaviors.
It is effective for people to establish epidemic prevention concepts. Wearing masks reduces the community positivity rate by 9.3%.
Five to nine weeks after the start of the experiment, the researchers successively investigated the symptoms of COVID-19 in the subjects, and 10 to 12 weeks later took blood samples from the intervention group and the control group to detect the number of COVID-19 antibodies in their bodies. .
After observation, the researchers found that the proportion of people in the control group who “wear masks correctly” was 13.3%, while the proportion of people in the intervention group was 42.3%. The proportion of people in the intervention group who wore masks correctly was about three times that of the control group. In addition, the proportion of people who complied with the “social distance regulations” was 24.1% in the control group and 29.2% in the intervention group. Although the gap was smaller than the former, the intervention group after counseling still had a higher value.
The researchers said that five months after the start of the experiment, the awareness of epidemic prevention in the intervention group gradually weakened, indicating that people began to relax their attitudes towards epidemic prevention. However, overall, the mask wearing rate of the intervention group was still 10% higher than that of the control group. %about.
In addition, in villages that received cloth masks and medical masks donated by the research team, compared with the control group, the number of patients with new coronary pneumonia symptoms decreased by 11.2%; the proportion was higher among the elderly. Elders over 60 years old in the villages usually When epidemic prevention measures are taken and masks are worn, the infection rate of patients with COVID-19 symptoms is reduced by 34.7%.
The researchers estimated that after the intervention coaching, the number of people wearing masks in the intervention group increased by 28.8%. When tracking subjects, the intervention group was 9.3% less likely to be tested positive for COVID-19 symptoms, and the number of COVID-19 symptoms increased by 9.3%. This further decreased by 11.9%.
Researchers track residents to reveal their secrets, which may add variables to experimental results
This study does show the benefits of wearing a mask during the COVID-19 pandemic, but the experiment still has limitations. For example, when researchers track whether local residents have implemented epidemic prevention measures, although the tracking researchers are very careful and wear casual clothes, the subjects may have recognized them, causing the subjects’ behavior to change, resulting in this The experiment added some uncontrollable factors. Furthermore, this study cannot explain why reducing people’s contact with each other and reducing viral vectors are related to wearing masks; and the experiment also cannot guarantee that masks can reduce more advanced infections.
In addition, research cannot determine whether wearing a “cloth mask” has the same anti-epidemic effect. Although the diagnosis rate of people wearing cloth masks has also declined, its effect is quite limited compared with medical masks, and its impact on blocking the spread of COVID-19 is even smaller than research data.
The experimental results are expected to end the academic debate on whether the popularization of masks should become the top priority for epidemic prevention.
Research leader Jason. Jason Abaluck said that this study has the opportunity to end the debate in the scientific community on “whether masks are effective in preventing epidemics.” He also said that if the wearing of masks is more common in a country or region, the positive rate of new coronary pneumonia will be lower. It will definitely not be reduced by only 9.3%, the value may be several times higher.
Meghan, an emergency medicine physician and professor at Brown University, is also a co-author of the study. L. According to Megan L. Ranney, this study contains three key observations:
First, this study provides more evidence that masks can protect the wearer and interrupt community transmission. However, because the research team could only record cases with COVID-19 symptoms and virus seropositivity, Ranney believes that this result may be an underestimate.
Second, this study shows that better quality masks can provide better protection against COVID-19.
Third, this study shows how to make epidemic prevention behavior a social norm through “wearing a mask” to encourage people to engage in more actions that are beneficial to epidemic prevention.
The research team concluded from this study: People should generally obtain masks and then accept the important concept of wearing masks taught by health units. Laney said that in April 2020, during the Trump administration, the U.S. Postal Service formulated a plan to send five masks to each household, but this plan was ultimately not implemented.
Ranney believes that if the research team sends masks to households in the United States in the same way as the participants in this study, will it be able to reduce the number of deaths caused by the new coronavirus in the United States? The answer will be quite intriguing.
source:
The Impact of Community Masking on COVID-19: A Cluster-Randomized Trial in Bangladesh
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