The World Health Organization yesterday recognized that in poorly ventilated rooms, coronavirus can travel throughout the room

 Say goodbye to the distances of two meters or six feet that supposedly could save us. Will not save. In a poorly ventilated room, the coronavirus can infect from the other end of the room.

"The coronavirus may linger in the air in crowded indoor spaces, spreading from one person to the next, the World Health Organization acknowledged on Thursday.

The W.H.O. had described this form of transmission as doubtful and a problem mostly in medical procedures. But growing scientific and anecdotal evidence suggest this route may be important in spreading the virus, and this week more than 200 scientists urged the agency to revisit the research and revise its position.

In an updated scientific brief, the agency also asserted more directly than it had in the past that the virus may be spread by people who do not have symptoms: “Infected people can transmit the virus both when they have symptoms and when they don’t have symptoms,” the agency said. Therefore, you can plug all the thermometers in your rear end. They will not help from those who spread the coronavirus but have no symptoms. And the temperature measurements in the rear end are the most accurate.

The W.H.O. previously said asymptomatic transmission, while it may occur, was probably “very rare.”

Some experts said both revisions were long overdue, and not as extensive as they had hoped.

An aerosol is a respiratory droplet so small it may linger in the air for hours. In its latest description of how the virus is spread, the agency said transmission of the virus by aerosols may have been responsible for “outbreaks of Covid-19 reported in some closed settings, such as restaurants, nightclubs, places of worship or places of work where people may be shouting, talking or singing.”

The W.H.O. had maintained that airborne spread is only a concern when health care workers are engaged in certain medical procedures that produce aerosols. But mounting evidence has suggested that in crowded indoor spaces, the virus can stay aloft for hours and infect others, and may even seed so-called superspreader events.

In addition to avoiding close contact with infected people and washing hands, people should “avoid crowded places, close-contact settings, and confined and enclosed spaces with poor ventilation,” the agency said, and homes and offices should ensure good ventilation.

People may need to minimize time indoors with others from outside the household, in addition to maintaining a safe distance and wearing cloth face coverings. Businesses, schools and nursing homes may need to invest in new ventilation systems or ultraviolet lights that destroy the virus."

Wearing a cloth face mask is too little when it comes to aerosols. You need to wear N95 masks (in Europe those masks are called FFP2/P2), which are now worn by all South Koreans. The WHO is silent about this for fear that the N95 masks will not be available in Africa at all if you wear them. N95 masks are easier to make than Musk's rockets for the conquest of Mars. If Africa stops dreaming of moving to Europe, it will be able to produce N95 masks easily.