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Researcher disputes ministry report dismissing mask benefits

A Helsinki University academic says a recent report on masks omitted the latest research by virologists on the subject.

Maskeja ulkona.
Finland has not recommended widespread use of masks as a means of slowing infection. Image: AOP
Yle News

There is ample research to support the widespread use of masks by the public, contrary to a report on the issue by the Ministry of Social Affairs and Health, according to one Helsinki University academic.

Tarja Sironen, an associate professor with the university’s emerging infectious diseases unit said that the report produced by private health sector consultants Summaryx for the ministry did not provide a full picture of the value of masks in slowing the spread of the novel coronavirus pandemic.

"Because of limited time it adopted a pretty narrow perspective. It is known that there are problems associated with using masks. If we take a broader view and [look at] what we have learned this spring, then we will also find a great deal of support for using masks," Sironen told Yle’s Ykkösaamu morning radio programme on Monday.

Mask use recommendations this week

This week the ministry will use the findings of the report to present the government with a proposal on whether or not to recommend the use of masks. The report reviewed eight studies on the use of masks by the public and concluded that there is little or no benefit to widespread use of the protective nose and mouth coverings.

Starting from Monday, many emergency measures introduced to slow the spread of the virus will be dismantled. Restrictions relating to gatherings and domestic leisure travel have been eased or lifted and the number of commuters on public transport has begun to rise since the end of May.

Many service providers are consequently considering how best to ensure safety as the circumstances change. For example, Helsinki Regional Transport (HSL) does not require passengers to use masks, but it has not forbidden them either. Meanwhile national railway VR has said that it will provide masks and hand sanitiser for passengers to purchase.

Many views on masks

There are many views on the benefits or lack thereof relating to protective masks. In some cases, they are not mutually exclusive, Sironen said. From the perspective of spreading infection, the central questions are: whom do masks protect and where should they be used?

According to Sironen, one of the many insights learned during the past spring is the fact that the virus behaves very differently from what experts expected. Sironen said that the literature review on mask usage omitted the latest research by virologists on the subject.

She mentioned as an example research in the journal Nature Medicine that focused on the effectiveness of surgical masks in patients with respiratory infections. The research subjects included patients suffering from diseases caused by novel coronavirus, as well as rhino and influenza viruses. Researchers measured how much of the microbes were able to pass through a mask and found that the coronavirus was trapped by it.

Sironen herself was involved in another study that looked at the spread of the virus in aerosols. It was part of a Aalto University study led by Ville Vuorinen that modelled the behaviour of aerosols containing the virus in indoor air streams. She noted that similar studies have also been conducted elsewhere.

"This new coronavirus spreads not only in droplets, but also in aerosols. It also changes [our] understanding of how to combat the virus," she added.

The Finnish research found that the virus can remain airborne and float for a distance of up to four metres. This means that hand washing can protect people from droplet infection, but not from aerosol infection.

"Droplet infection can to a large extent be prevented by hand washing because heavy droplets quickly fall to surfaces where our hands can come into contact with them. The importance of this is now diminishing. We now understand that infection caused by breathing in aerosols is more significant and therefore a mask is absolutely a good method -- in addition to avoiding contact. If you cannot avoid contact, then a mask is a huge help," Sironen explained.

Masks "a good starting point"

There are many different kinds of masks and face protectors in use and available for sale. The level of protection provided by different models also varies. According to Sironen, virtually all face protectors have been found to reduce the exhalation of microbes to some extent. But she said that it is the big picture that matters.

"It’s a question of how far masks provide protection. It is as important to protect others as it is to protect oneself -- to protect risk groups and to stop the epidemic from spreading," she noted.

She added that when it comes to fabric masks, the material and shape determine how effectively they can provide protection. Usage time and washing are factors that can affect the level of protection offered.

The literature review that formed the basis for last Friday’s report did not offer solid grounds for making a clear recommendation on mask usage in Finland.

However Sironen called for the authorities to advise using masks.

"I would hope for some kind of recommendation on mask use to protect risk groups and it would be a good starting point in crowded indoor spaces," she said.

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