Can buying a drink time spread the virus? Expert: Masks may need to be upgraded

At the press conference on the prevention and control of the epidemic in Shanghai held on January 13, the Shanghai Municipal Health Commission reported that in the routine nucleic acid testing of the new crown pneumonia virus by the relevant isolation and control personnel of a case of asymptomatic infected person imported from abroad reported by the city on January 11, 5 people with abnormal test results were found, of which 2 cases were locally confirmed cases of new crown and 3 cases were asymptomatic infected people.

It is worth noting that among the 5 people who tested positive for nucleic acid, 3 cases were the clerks who contacted the above-mentioned asymptomatic infected people imported from abroad when purchasing milk tea, and judging from the action trajectory announced by the asymptomatic infected person imported from abroad, they did not stay in the milk tea shop for a long time.

In the time of buying a cup of milk tea, asymptomatic infected people can spread the virus to each other. We can't help but ask, can wearing a mask protect against viruses?

According to the epidemic prevention requirements, restaurant staff should wear masks, and overseas imported personnel who are still in the 7-day health monitoring period should also wear masks. Customers leave after buying milk tea, and in the process of this short contact, the virus can still be successfully transmitted, which should be paid enough attention to, ordinary masks may not be able to stop the spread of the new crown virus.

The first financial reporter inquired about the latest disease prevention tips released by the Shanghai Center for Disease Control and Prevention in January, requiring people to wear masks in closed places such as public transportation, elevators, public toilets and outdoor places where people gather; maintain a social distance of 1 meter. The tip does not emphasize what kind of mask people should wear. With the emergence of the highly contagious Omiljung variant, public health experts believe that the current masks may need to be upgraded.

We already know that asymptomatic infected people can spread the virus, and the latest research has found that the Omiljung variant can multiply in large numbers in the upper respiratory tract. "Now the smart thing to do is that you should wear a mask that is more protective." A public health expert told the first financial reporter.

At the beginning of the COVID-19 outbreak, there was scientific data showing that the virus can be transmitted through aerosols, and wearing a mask can reduce the spread of the virus. At the height of the first wave of the global epidemic, the more protective medical-grade masks N95 and KN95 were in short supply in many countries, but since then, as the epidemic has gradually eased, more people have chosen to wear lighter disposable surgical masks or reusable single-layer cloth masks.

With the acceleration of the new round of the epidemic, this general surgical mask may have been difficult to prevent a highly contagious virus like the Omikerong variant. In Europe, public health agencies in countries such as Germany and Austria have changed their recommendations on standards for people to wear masks, stipulating that masks above the medical level must be worn in public places such as buses and streets.

The Centers for Disease Control and Prevention (CDC) is also considering re-evaluating guidelines for masks, which may recommend that people choose highly protective N95 or KN95 masks worn by healthcare workers.

Recently, the French mask manufacturers union also claimed that in the face of the Olmi kerong variant, the protective effect of surgical masks is poor, and the organization recommends the use of FFP2 masks, which is equivalent to N95 masks in the United States. The French government said it was awaiting the opinion of the High Council on Public Health.

A study published last December in the Proceedings of the National Academy of Sciences (PNAS) showed that in the case of two people wearing masks and the infected person is talking, the chance of being infected by the new crown virus is about 30% if they are wearing a surgical mask, while if they wear an FFP2 mask, the chance of being infected in the same situation is only 0.4%.

Erin Bromage, an associate professor of biology at the University of Massachusetts Dartmouth, believes that an important factor driving changes to the mask guidelines is that people have a better understanding of the new coronavirus and how it spreads. "It took a long time to understand the nature of the spread of the new coronavirus through aerosols, and the flu is more transmitted through droplets, but the main driver of the spread of the new crown virus is airborne transmission." Bromage said.

According to the CDC, N95 masks approved by the National Institute for Occupational Safety and Health can filter up to 95% of particulate matter in the air. Bromage said surgical or disposable masks are 5 to 10 percent less effective than N95 masks.

He also suggested that wearing masks with a higher level of protection could actually prolong the time it takes for the virus to get infected. "The role of masks in this regard is to reduce the viral load that people actually inhale, which means that it takes longer to be infected." He explains, "If your mask can block half the virus, then it will take you twice as long to get infected, and if your mask can block 90% of the virus, it means that it will take 10 times longer for you to be infected, which greatly reduces the chance of being infected." ”