The coronavirus has been infecting people worldwide for over half a year now. We know more and more about the disease that causes Covid-19. It plays a substantial role in our lives nowadays and many statements are made about the virus. Thierry Baudet, leader of the Dutch political party Forum for Democracy (FVD) said, at a Dutch program that the chance to get infected in an outdoor environment is very small. His statement is mostly true.
The leader of FVD made his statement in the Dutch television show ‘Goedemorgen Nederland’ on June first. He did not mention a source to substantiate his statement and his statement also lacked an exact number. On the same day he visited the Dutch city Volendam for the re-opening of restaurants and cafés and made the same statement on RTL Boulevard. FVD politicians visited this city to protest against social distancing in The Netherlands, the 1.5 meter rule.
A survey from Hongkong, dated 7 April, showed that only one in 7324 infections has occurred in an outdoor environment. This survey was led by Li Yuguo from the University of Hongkong. A 27 year old man, who was having a talk with somebody who returned from hotspot Wuhan was infected with the coronavirus. Director of the Dutch Centre of Infection control from the National Institute for Public Health and Environment (RIVM), Jaap van Dissel, said to the Dutch newspaper ‘The Volkskrant’ that the risk outside is indeed smaller than inside, because it gets blown away and because of the UV-light of the sun. In his technical briefing, on 4 June, he partly returned from this statement. He claimed that there has not been sufficient research on the infection risk in an outdoor environmental versus an the indoor environmental. According to Van Dissel the survey from Hongkong has been done in a period when people in China had to stay inside. ‘’Besides, this survey was done is a period where people would not leave their homes due to the weather conditions. And even when someone stepped outside, there was nobody else in the streets, because everybody had to stay inside’’, according to Jaap van Dissel.
Nevertheless he added that there are very good reasons to assume that the risk is more critical in an indoor environment than in an outdoor environment, but the virus could still be transferred outdoors. A good reason to maintain the one and a half meter rule, he argued.
Japanese researchers came to a similar conclusion with a similar research on 16 April. They consider it plausible that the transferring of the virus in an indoor environment is 18,7 times higher than in an outdoor environment. They researched 110 cases. The renown Dutch pollster Maurice de Hond mentioned this number on television in the Dutch news programme ‘EenVandaag’. Virologist Ab Osterhaus said to EenVandaag that this is not a holy number. Despite that he acknowledged that the chance to get infected is way larger in an closed room, than outside. He explained that there is more ventilation outdoors and people can keep more distance. The first factor is harder to arrange indoors.
Also engineer Atze Boerstra from ‘BBA Binnenmilieu’ (BBA indoor environmental) told EenVandaag that the chance to get infected indoors is larger than outdoors, because the gathering of people indoor is more likely and frequent than outdoor. And a lot of indoor-environments are badly ventilated.
On 30 May some virologists made a call in the Dutch newspaper ‘Algemeen Dagblad (AD)’. They advised a less strict maintenance of the one and a half metre rule outside. Louis Kroes form the Leiden University Medical Centre (LUMC) says that the transferring of the virus happens way less often outside than inside. Although she emphasized that there is a chance that the virus will spread outside, she states that this will not result in a fast spread of the pandemic. Virologist Coretta van Leer of the University Medical Centre Groningen underscored again the importance of ventilation.
The statement that the chance to get infected in an outdoor environment is smaller than inside, is mostly true. Because of the lack of exact figures, in this stage of the pandemic, we cannot determine with certainty that this is completely true for the spread of coronavirus. Experts agree that most infections have occurred indoors. They furthermore agree that due to ventilation and more options to keep 1.5 meter distance, chances are smaller to get infected with coronavirus in an outdoor environment.
RESEARCH | ARTICLE : Sebas Lammers
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