Scientific evidence is clear: Social distancing and wearing masks help prevent people from spreading COVID-19, and masks also protect those who wear them, two 新澳门六合彩内幕信息 Davis Health experts said on 新澳门六合彩内幕信息 Davis LIVE: COVID-19.
A range of new research on face coverings shows that the , said Dean Blumberg, chief of pediatric infectious diseases at 新澳门六合彩内幕信息 Davis Children鈥檚 Hospital.
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鈥淥n the issue of masks, I鈥檇 like to restart 鈥 because we鈥檝e learned a lot,鈥 Blumberg said. 鈥淲e鈥檝e learned more due to research and additional scientific evidence. What we know now is that masks work and are very important.鈥
Blumberg and William Ristenpart, a professor of chemical engineering at 新澳门六合彩内幕信息 Davis, appeared on the July 2 livestream devoted to explaining how the virus spreads and how to prevent transmission.
In their comments and answers to questions from viewers, Blumberg and Ristenpart repeatedly made the point that research continues to support the fundamental methods to prevent spreading COVID-19: Wear masks, maintain social distance and keep social interactions outdoors whenever possible.
Transmission by droplets
There are two primary methods of transmission, they said. The first is via droplets a carrier expels, which are about one-third the size of a human hair but still large enough that we can see them. Masks create an effective barrier against droplets.
鈥淓veryone should wear a mask,鈥 Blumberg said. 鈥淧eople who say, 鈥業 don鈥檛 believe masks work,鈥 are ignoring scientific evidence. It鈥檚 not a belief system. It鈥檚 like saying, 鈥業 don鈥檛 believe in gravity.鈥
鈥淧eople who don鈥檛 wear a mask increase the risk of transmission to everyone, not just the people they come into contact with. It鈥檚 all the people those people will have contact with. You鈥檙e being an irresponsible member of the community if you鈥檙e not wearing a mask. It鈥檚 like double-dipping in the guacamole. You鈥檙e not being nice to others.鈥
Transmission by aerosol particles
The second major transmission method is via the aerosol particles we expel when we talk. Those are about 1/100th the size of a human hair and are more difficult to defend against. Social distancing and staying outdoors, where there is more air flow, are helpful, Blumberg and Ristenpart said.
鈥淪tudies in laboratory conditions now show the virus stays alive in aerosol form with a half-life on the scale of hours. It persists in the air,鈥 Ristenpart said. 鈥淭hat鈥檚 why you want to be outdoors for any social situations if possible. The good air flow will disperse the virus. If you are indoors, think about opening the windows. You want as much fresh air as possible.鈥
This is why, he said, places like bars are particularly hazardous for aerosols, on top of the likelihood of minimal distancing. 鈥淭he louder you speak, the more expiatory aerosols you put out,鈥 he said.
Other topics
Plexiglass and cubicles as protection? 鈥 The plexiglass shields in stores and restaurants only help somewhat. The same is true for office cubicles. But after a lengthy time, transmission is possible from aerosols if the air flow is not good, they said.
鈥淭he way to think about that is to think about smells,鈥 Ristenpart said. 鈥淚f the person on the other side of a cubicle or plexiglass is wearing perfume, eventually, you鈥檒l smell it. The aerosol particles are small enough to travel on air much like aromas. That鈥檚 why air flow is so important, along with other actions like wearing masks and social distancing.鈥
Time of exposure matters 鈥 鈥淚f you鈥檙e going past someone very quickly in a grocery store,鈥 Blumberg said, 鈥渢he risk of getting infected is very low. It鈥檚 really lingering and talking that does it.鈥
Ristenpart added: 鈥淚t鈥檚 really important to know that just because you鈥檙e standing 6 feet or 7 feet away, if you have a prolonged conversation, there is still a risk. These aerosols can be carried along on weak air currents.鈥
Surface contact is less of a threat 鈥 There is no precise research on the prevalence of transmission from hand contact. 鈥淔or ethical reasons, we can鈥檛 contaminate a bunch of people鈥檚 hands, then have them touch their faces or other people鈥檚 faces,鈥 Ristenpart said. 鈥淏ut backtracking infections and following transmission events shows surfaces or hand contacts are not a primary method.鈥
Which brings researchers back to droplets and aerosol particles as the primary methods of transmission.
鈥淲e know from other coronaviruses that this is primarily a respiratory transmitted illness,鈥 Blumberg said. 鈥淭here is a very small chance of transmission via groceries or mail or things like that. But washing hands is still always good.鈥
Children and COVID-19 鈥 Children are less likely 鈥 by half 鈥 to be infected if they are exposed, less likely to be symptomatic and less likely to have a severe case if they do get sick, Blumberg said.
鈥淭hey appear to be less likely to infect others,鈥 he said. 鈥淭his is different from other infections like the flu when they are carriers. This appears to be much more of an adult disease. But children can still get sick and can still transmit it to others, so it鈥檚 important to be as hygienical with them as their development allows.鈥
Evidence on social distancing and masks
An international team of researchers published an analysis of the effects of social distancing, masks and other measures on COVID-19 on June 1 in The Lancet. .
Connecting the research
Both scientists said the evidence has become even more powerful for wearing masks and social distancing. For instance, research shows that about 30 percent of infections are caused by people who do not know they have COVID-19 because they are asymptomatic or their symptoms have not appeared yet.
鈥淪o we don鈥檛 know who might spread it,鈥 Blumberg said. 鈥淲e do know social distancing reduces the risk of transmitting the virus by 90 percent, and wearing masks decreases the risk by 65 percent.
鈥淲earing a mask affects everyone,鈥 he said. 鈥淚f you care about your family or friends, or if you care about your community, wear a mask.鈥