Scientists again warn of corona contamination via airborne particles.

How has global thinking changed, and is the Netherlands out of step?

This article is from Trouw.

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Aerosols, liquid particles carried by air: they are the talk of the town again. On Thursday, 39 scientists again called for more attention to good ventilation to prevent corona contamination. They did so in an opinion piece in the scientific journal

Science

. Their story is not new: the same scientists already sent an open letter to the World Health Organization WHO in July. Then their call was still controversial. Much less now.

What was that again?

Especially medical scientists, such as virologists and epidemiologists, insist that you only (or mainly) become infected through larger droplets, which fall to the ground within 1 meter.

Researchers from the field of physics argue that it occurs to a large extent via smaller particles that float further.

For example, they explain mega outbreaks in choirs, for example.

If aerosols play a significant role, it is important to properly ventilate indoor areas.

Position has shifted considerably

The position of the WHO, the organization that coordinates the global approach to the epidemic, has shifted considerably.

At the beginning of October, the WHO wrote on its website that the virus is only transmitted via larger droplets, for example with coughing and sneezing.

Later that month, the WHO reported that aerosols also transmit the virus in certain circumstances.

"Further research is underway," the WHO wrote at the time.

For the past two weeks, the organization has stated plainly that aerosols can spread the virus in 'poorly ventilated and / or busy indoor conditions'.

The WHO adds that transmission within one meter is most common, whether through large droplets or aerosols.

So keeping your distance remains important.

The American CDC goes further: it now even mentions contamination via inhaled aerosols before contamination with droplets on the website.

The Belgian RIVM, Sciensano, already warned in November about the role of aerosols.

At the end of April, the ventilation task force set up by the government recommended installing a CO2 meter in every room where people are staying, which gives an indication of the amount of exhaled air in a room.

If this is not available, one square meter of open window is needed per four people, the Belgian task force advises.

And in the United Kingdom, good ventilation is one of the four basic rules, in addition to keeping your distance, wearing a mouth mask and washing hands.

Netherlands: 'not clear'

And the Netherlands?

Here the attitude remains double.

On the one hand, the RIVM has also pointed to the importance of ventilation to prevent the transmission of covid since last summer.

The cabinet made money available to better ventilate schools, although the installation of ventilation systems hardly got off the ground there.

On the other hand, ventilation in the Netherlands is not one of the basic rules of 'washing, distance, testing'.

And where the WHO has attributed a role to aerosols since the end of October, the RIVM still states that it is 'unclear' whether airborne transmission 'plays a relevant role' in the spread.

Transmission does indeed take place via suspended particles, said Jaap van Dissel, head of infectious disease control, this week in the House of Representatives.

But, he insists, their contribution to the spread of the virus is small.

Number of COVID-19 patients in hospitals is declining

The decline in the number of COVID-19 patients in hospitals continues.

2,250 COVID-19 patients have now been admitted, more than 250 less than a week ago.

728 patients are in intensive care, 1,522 in a nursing ward.

On average, 32 patients were admitted to the ICU per day last week, 14 fewer than last week.

An average of 204 patients per day came in to the nursing wards, 27 fewer than last week.

On Friday, 5,608 positive corona tests were reported to the RIVM.