The common belief that you can’t contract Corona outdoors could be disproved because of the more contagious Delta variant.
Sitting on restaurant terraces again, meeting with the big group of friends in the park or in the countryside for sports: Outdoors and in summer, you can hardly catch Corona, is a common belief in the pandemic. The mask or the distance are sometimes forgotten. But this can take its toll: With the delta variant now prevalent, it could also happen, depending on the situation, that the virus jumps outdoors.
Fivefold increase in viral load
“Delta is generally more contagious – that also applies when you’re out in the fresh air,” said Ralf Bartenschlager, president of the German Society for Virology. “It was possible to become infected outdoors even with earlier variants, but the probability of it happening increases with delta,” explained the expert from the University of Heidelberg. Delta-infected people would have a viral load presumably increased by a factor of five compared to the predecessor variant Alpha (B.1.1.7).
“The more virus present in an infected person, the greater the risk of transmission – even outdoors.” Whether infection occurs, however, always depends on many other factors – outdoors, for example, how closely people stand together. “There’s no blanket way to say how quickly an infection can happen – it might take a minute or it might take an hour.”
1,000 infections at music festival
It was only in mid-July that it became known that at least about 1,000 visitors had been infected with the coronavirus at a music festival in Utrecht in the Netherlands. About 20,000 people had attended the two-day open-air festival earlier that month. Organizers reacted in shock.
So in such outbreaks, there is always the question of whether people kept their distances, whether they wore masks, and whether there was closer contact in certain places, such as waiting outside restrooms or other locations. Activity at an event is also likely to play an important role: Singing loudly, for example, increases the emission of aerosols.
Increased risk of infection
However, aerosol expert Gerhard Scheuch continues to assume that people become infected particularly indoors. Should the risk of infection actually increase outdoors, this would mean that this would be even more true for indoor areas, he said in response to a question. At soccer matches and festivals in particular, many people share certain rooms, for example on the journey, when staying overnight or in the toilets. Thus, it can be assumed that many of the infections that were recorded in connection with open-air events could have taken place indoors.
Evidence of outdoor transmission
The German Robert Koch Institute (RKI) stated on request that it had no changed assessment: The institute’s website states that transmissions rarely occur outdoors overall and account for a small proportion of the total. If the minimum distance is maintained, the probability of transmission in outdoor areas is “very low” because of air movement. However, the RKI recommends keeping a distance of at least one and a half meters and avoiding large gatherings of people, even outdoors, so that fewer droplets and aerosols are directly exposed.
The World Health Organization (WHO) recently also pointed to a study from China that substantiates the danger of delta: There, people were examined who were in quarantine after contact with a delta-infected person. The PCR test was positive after an average of four days instead of six days for early variants. In addition, the viral load on the first positive test was 1,200 times higher compared with original variants, he said. “This suggests that this variant of concern may replicate more rapidly and be more contagious in the early stages of infection,” WHO said.
— source: heute.at/picture:pixabay.com
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