Outside and in summer you can hardly get infected with Corona, is a common belief in the pandemic. The mask or the distance are sometimes forgotten. But that can take revenge: With the delta variant, which is now also prevalent in Germany, depending on the situation, it could more likely happen that the virus also skips outdoors. “Delta is generally more contagious – that also applies when you are in the fresh air,” says the President of the Society for Virology, Ralf Bartenschlager. “You could get infected with earlier variants outdoors, but the probability of it happening increases with Delta.”
Compared to the predecessor variant Alpha (B.1.1.7), people infected with delta have a viral load that is probably five times higher, says the expert from the University of Heidelberg. “The more virus there is in an infected person, the greater the risk of transmission, even outdoors.” Whether there is an infection always depends on many other factors – outside, for example, how close you are. “There is no general way of saying how quickly an infection can happen – it might take a minute or an hour.”
Infection indoors or outdoors?
It was only in mid-July, for example, that it became known that at least around 1000 visitors had been infected with the corona virus at a music festival in Utrecht in the Netherlands. Around 20,000 people attended the two-day open-air festival earlier this month. However, aerosol expert Gerhard Scheuch continues to assume that people become infected, especially indoors. Should the risk of infection actually increase outdoors, that would mean that this would apply even more to indoors. At soccer games and festivals in particular, many people shared certain rooms, for example on the way to the hotel, when staying overnight or in the toilets. One could assume that many of the infections that were recorded in connection with open-air events could have taken place in rooms after all.
With outbreaks like this, the question is always whether people kept their distance, whether they wore masks and whether there was closer contact in certain places, for example when waiting in front of the toilets or in other places. The activity at an event should also play an important role: if you sing loudly, for example, there will be increased emissions of aerosols.
The US epidemiologist Eric Feigl-Ding showed up on Twitter recently concerned about what he believed to be evidence of outdoor broadcasts. He also referred to the alleged contagions in India at religious events, which were largely held outdoors. He has also warned for a long time that Delta could be transmitted in the event of fleeting encounters.
On request, the Robert Koch Institute (RKI) announced that it had not changed its assessment: On the institute’s website, it was said that broadcasts in the outdoor area were rare and that they had a small share in the overall event. If the minimum distance is maintained, the probability of transmission outdoors is “very low” because of the air movement. The RKI also recommends maintaining a distance of at least one and a half meters and avoiding large crowds outdoorsso that you get fewer droplets and aerosols directly.
The World Health Organization (WHO) recently also had on a study from China pointed out that underpin the dangerousness of Delta: People were examined there who were in quarantine after contact with someone infected with Delta. The PCR test was positive for them after an average of four days instead of six days, as was the case with the early variants. In addition, the viral load was 1200 times higher in the first positive test compared to the original variants. “This suggests that this worrying variant may reproduce more quickly and be more contagious in the early stages of infection,” the WHO said.