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Grappling with inconclusive Covid-19 science during a pandemic — an interview with Professor Antoine Flahault

Antoine Flahault, Director of the Institute of Global Health at the University of Geneva. Source: Antoine Flahault.

We’re now six months into the pandemic, but the rapidly evolving science behind Covid-19 has complicated efforts to clamp down on the virus’ rampage around the world. Geneva Solutions asked Antoine Flahault, director of the Institute of Global Health at the University of Geneva, and leading voice on Covid-19 science in the region, how we can take swift action to save lives when science hasn’t yet provided definitive answers.

When we don’t have evidence, scientists need to be transparent, he says. In the meantime, masks for everyone, everywhere, and all the time, are vital to fend off the pandemic.

Geneva Solutions — Earlier this year, you advocated homemade masks out of toilet paper on Twitter, even though there was no scientific backing for your claim. Why?

Professor Antoine Flahault — It’s true that in late January when COVID-19 began its rampage around the globe, there wasn’t enough evidence to suggest that homemade masks actually worked. I made an assumption that any physical barrier was better than no protection at all. Some of my colleagues said it was irresponsible to make claims on homemade masks without scientific data to back them. At the same time, my colleagues weren’t providing any alternatives to fend off the virus, and there was a massive shortage of surgical masks.

During a crisis, doing something is better than doing nothing. In the case of masks, wearing a mask is a really low-risk action that has a huge potential benefit in preventing onwards transmission. When the evidence isn’t there, we need to be transparent and mention the lack of scientific evidence and use our gut feeling because the data may take time to collect — and in that time, lives can be saved. And we shouldn't be stubborn when the evidence comes our way. We should follow it. In the case of masks, evidence eventually came that masks provide very useful and effective protection against the coronavirus.

However, we wouldn't want to follow our gut in other instances. For instance, we cannot trust that an untested vaccine works. However, in the case of masks, there is very little risk associated with mask-wearing, and a very large potential benefit, but this is not the case with an untested vaccine, which could have dangerous side effects.

There’s a similar lack of clarity on aerosol transmission of COVID-19. Some scientists think aerosols are primary drivers of transmission, while others — including the WHO — maintain that they are not a primary route of transmission. What should we do when the science is unclear?

Aerosols are small viral particles that float around in the air. We think they’re produced when people speak, sing, cough, sneeze or exhale, but the data is still limited. However, our lack of solid evidence shouldn’t nullify the aerosol hypothesis. Maybe aerosols are not the major route of transmission of Covid-19, but we just don’t know yet.

What we can do now is to protect ourselves with masks in closed spaces that lack ventilation. Keeping distance may simply not be sufficient. We need to be sensible and do the best we can with the tools we have — and that means wearing masks.

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Masks should be worn everywhere, all the time, by everyone - including pupils in classrooms. Source: UNICEF.

We are approaching the fall start of schools. Is there a risk that opening up schools could endanger children?

The latest science tells us that pupils, and anyone below the age of 40, is at a very low risk of becoming critically ill and dying from COVID-19, so opening schools will not endanger children themselves. Rather, the issue is that children could transmit the virus to others in their surroundings, particularly vulnerable groups like older people, those with underlying conditions or even school teachers and staff.

Could schools become a breeding ground for Covid-19 transmission?

Definitely. Given that classrooms in schools are often enclosed and poorly ventilated, schools have potential to turn into clusters of transmission that could spill over into the community.

Some epidemiological findings also suggest that children — and even young children — may transmit the virus as well as adults. This is based on evidence that children carry similar quantities of the virus as adults in their noses and throats. However, we’re still not totally sure whether that means they can transmit as well as adults. Given the data is not well ascertained, we need to stay cautious, and take appropriate measures to mitigate the spread of the virus.

Do you see concrete good practice examples that countries could emulate — in Europe and beyond — with regards to smaller class sizes, masks, remote learning, or other measures, to curb the risk of transmission in schools?

There are three measures we can take to win against this virus and allow schools to stay open for as much as possible throughout the year:

  1. The most important measure we can take is to wear masks in schools throughout the day. Wearing masks is possible for any child older than 3 years of age

  2. We need to improve ventilation in schools, and we also need to promote alternative methods of teaching to reduce the number of students in one space at any point in time. We can achieve the latter by spreading out lunch breaks throughout the day so that kids aren’t all eating at the same time. We could even spread out the time for going to school — not for primary schools because younger children are less autonomous, but maybe for children in secondary schools. This may also take the edge off overcrowded public transportation, and contribute to dampening down transmission.

  3. We could also implement distance learning or mixed approaches in secondary schools. However, we need to stay cautious, because not all parents will be able to stay at home to supervise their childrens’ learning. Also, not every family will have computers at home, so we need to take the context into account. There’s also the issue of meals at schools. We need to bear in mind that schools may offer more nutritious meals than at home. That’s why we need to carefully consider the context and work accordingly, and to ensure the strategies we adopt are sensible and appropriate.

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Remote learning may help curb Covid-19, but it won't be appropriate in all contexts. Source: Nenad Stojkovic.

We are seeing a slow, but steady rise in new Covid cases in Switzerland from 100 a few weeks ago to over 200 new cases in the past week. Is there anything Switzerland could do to further curb transmission?

There are several measures Switzerland can adopt today, and that’s to recommend wearing masks in all indoor settings, not only in public transportation, but also in workplaces and businesses in the whole nation. These are the next breeding grounds for transmission.

The second measure we can take is to learn from countries like Australia, Taiwan and Japan. They took very targeted approaches to COVID-19 screening. Instead of randomly testing the entire population, their testing is precise, agile and swift. They took a proactive approach to identify superspreaders and clusters of COVID-19 cases. Once they found a cluster, they very quickly started testing and tracing before the cluster went out of hand and spread across the region.

Targeted screening approaches will be particularly important during the cold season, which will bring many people with mild symptoms to hospitals. If we don’t take more targeted approaches, it will be difficult to tease out COVID-19 symptoms from common colds caused by respiratory viruses other than Covid-19.