Research: Norway says ‘200,000 people would need to wear face masks to prevent one new infection per week’
A
report from the Norwegian Institute of Public Health has
reviewed the evidence on whether individuals in the community who don’t have Covid-19 symptoms should wear face masks to reduce the spread of the virus. It says randomised trials show a small protective effect from wearing medical face masks, but a nationwide training programme would be needed as incorrect use limits their effectiveness. On the use of non-medical face masks, it says there is ‘no reliable evidence’. The review concludes that, with infection rates low in Norway, ‘assuming that 20% of people infectious with Sars-CoV-2 do not have symptoms, and assuming a risk reduction of 40% for wearing face mask, 200,000 people would need to wear facemasks to prevent one new infection per week in the current epidemiological situation’. So, ‘wearing face masks... is not recommended for individuals in the community without respiratory symptoms’. Last week, Norway carried out 446 tests and had one positive diagnosis per 100,000 people; the UK carried out 1,240 pillar 1 and 2 tests and had five positive diagnoses per 100,000 people.
On my earlier thoughts of herd-immunity 20% (the science for this virus hasn't been proved either way so don't be too sure of yourselves).
The virus paradox
Yet another case has emerged of Covid-19 going into apparent retreat once around a fifth of a population has been infected. Serological tests on 21,387 residents of Delhi by the Indian Centre for Disease Control
suggest that 23.5 per pent of the city’s population have antibodies to Sars-Cov-2, the virus which causes Covid-19. Remarkably, this is a higher proportion than has been measured in New York, where 22.7 per cent were found to have been infected with the virus. The tests in Delhi were carried out between 27 June and 10 July. Since then, the epidemic seems to have peaked and receded.
The infection rate comes as a surprise given Delhi’s relatively low numbers of deaths. As the population of Delhi’s National Capital Territory is 16 million, the antibody figures suggest that 3.76 million people in the city have been infected. Up until Saturday, the Indian government had recorded 3,571 deaths in Delhi. That would give an Infection Fatality Rate (IFR) of just 0.094 per cent – far lower than the estimates of 0.5 per cent to 1 per cent suggested by the experience of European and North American countries and no higher than seasonal flu.
There are some questions over the reporting of Covid deaths in Delhi.
According to Indian newspaper the
Print, Delhi’s three municipal authorities have individually reported 4,155 deaths – higher than the government’s figures for the city. However, the higher figure does not significantly change calculations for the IFR – it is still well below estimates in the west.
The Delhi figures reveal a paradox which is becoming increasingly clear across much of the world: Covid-19 seems to be turning out to be a good deal less deadly in the developing world than in Europe and North America. Fears that inferior healthcare services would lead to an explosion in deaths in developing countries have not been borne out. Perhaps they have been affected by milder strains of the virus. The younger age profiles and lower obesity rates in developing countries may well be a factor. Moreover, there may be a different age profile of those infected: one of the factors in countries with very high death rates, such as Italy, Spain and Britain, is how the infection was able to rage in care homes back. There is also the possibility that people in some parts of the world have gained some kind of immunity to Covid-19 thanks to having been exposed to a similar coronavirus in the past.
The news from Delhi does not suggest that India’s strict lockdown was any more effective than that in Britain. But it does provide hope that the global pandemic will prove a lot less deadly than many have feared.
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Just trying to make you feel better.
And @JoeyD a quote from you pdf you posted in the small print at the end.
One study showed that a 12- layered cotton mask was as effective as a surgical mask, but a single- layered cloth mask was not protective against beta- coronaviruses.(Which includes Covid-19)
And
@FPV MIC on the 30 year-old who died after a covid party.
https://www.wired.com/story/the-latest-covid-party-story-gets-a-twist/
