More-rigorous analyses added direct evidence. A preprint study4 posted in early August (and not yet peer reviewed), found that weekly increases in per-capita mortality were four times lower in places where masks were the norm or recommended by the government, compared with other regions. Researchers looked at 200 countries, including Mongolia, which adopted mask use in January and, as of May, had recorded no deaths related to COVID-19. Another study5 looked at the effects of US state-government mandates for mask use in April and May. Researchers estimated that those reduced the growth of COVID-19 cases by up to 2 percentage points per day. They cautiously suggest that mandates might have averted as many as 450,000 cases, after controlling for other mitigation measures, such as physical distancing.
"You don´t have to do much math to say this is obviously a good idea," says Jeremy Howard, a research scientist at the University of San Francisco in California, who is part of a team that reviewed the evidence for wearing face masks in a preprint article that has been widely circulated6.
https://www.nature.com/articles/d41586-020-02801-8#ref-CR6
På linet kan man også læse om en anden dansk læge, Christine Benn, der er i gang med et stort randomiseret studie på Guinea-Bissau.
Benn´s team, working independently of Benfield´s group, is in the process of enrolling around 40,000 people in Guinea-Bissau, randomly selecting half of the households to receive bilayer cloth masks - two for each family member aged ten or over. The team will then follow everyone over several months to compare rates of mask use with rates of COVID-like illness. She notes that each household will receive advice on how to protect themselves from COVID-19 - except that those in the control group will not get information on the use of masks. The team expects to complete enrolment in November.
Man kan dog også læse om nogle forskere betænkeligheder ved netop randomiserede studier i forbindelse med Covid-19. Altså samme metode som det endnu ikke offentliggjorte danske studie har brugt.
Several scientists say that they are excited to see the results. But others worry that such experiments are wasteful and potentially exploit a vulnerable population. "If this was a gentler pathogen, it would be great," says Eric Topol, director of the Scripps Research Translational Institute in La Jolla, California. "You can´t do randomized trials for everything - and you shouldn´t." As clinical researchers are sometimes fond of saying, parachutes have never been tested in a randomized controlled trial, either.
Det kan, måske, være en af årsagerne til at det danske studie er blevet afvist af de tre store tidsskrifter.
"You don´t have to do much math to say this is obviously a good idea," says Jeremy Howard, a research scientist at the University of San Francisco in California, who is part of a team that reviewed the evidence for wearing face masks in a preprint article that has been widely circulated6.
https://www.nature.com/articles/d41586-020-02801-8#ref-CR6
På linet kan man også læse om en anden dansk læge, Christine Benn, der er i gang med et stort randomiseret studie på Guinea-Bissau.
Benn´s team, working independently of Benfield´s group, is in the process of enrolling around 40,000 people in Guinea-Bissau, randomly selecting half of the households to receive bilayer cloth masks - two for each family member aged ten or over. The team will then follow everyone over several months to compare rates of mask use with rates of COVID-like illness. She notes that each household will receive advice on how to protect themselves from COVID-19 - except that those in the control group will not get information on the use of masks. The team expects to complete enrolment in November.
Man kan dog også læse om nogle forskere betænkeligheder ved netop randomiserede studier i forbindelse med Covid-19. Altså samme metode som det endnu ikke offentliggjorte danske studie har brugt.
Several scientists say that they are excited to see the results. But others worry that such experiments are wasteful and potentially exploit a vulnerable population. "If this was a gentler pathogen, it would be great," says Eric Topol, director of the Scripps Research Translational Institute in La Jolla, California. "You can´t do randomized trials for everything - and you shouldn´t." As clinical researchers are sometimes fond of saying, parachutes have never been tested in a randomized controlled trial, either.
Det kan, måske, være en af årsagerne til at det danske studie er blevet afvist af de tre store tidsskrifter.