From number-crunching to chemistry: how research is used in the coronavirus outbreak

As the world comes to terms with the scale of the coronavirus pandemic, confusion reigns about the reliability and relevance of many statistics. While the death toll continues to rise, the total number of infections is impossible to know and estimates of the fatality rate continue to vary.

From number-crunching to chemistry: how research is used in the coronavirus outbreak
Photo: Stockholm University

The crisis has been made worse by shortages of essential medical supplies, which has led to chemists and other researchers at Stockholm University teaming up to solve the problem.

With no vaccine and no effective treatment, one thing that is abundantly clear is that there is no magic solution. But Tom Britton, professor of mathematics at Stockholm University and a specialist in modelling the spread of infectious diseases, says there is a magic number for public health experts to keep in mind: R = 1. 

The reproduction number (R) is the number of individuals the average person with the virus infects early in an outbreak; knowing that allows models to predict its spread. Many estimates put the global reproduction number for coronavirus at 2 to 2.5. By comparison, Professor Britton says it is roughly 1.5 for flu and 15 for measles. 

“With coronavirus, there’s no immunity and no vaccine, so even if R was 1.5 more than half would get infected,” he says. “At 2.5, then 60 to 70 percent would be infected if no restrictions or measures are implemented. That shows how much we must change our behaviour.” 

Those changes are to help us get below the magic number: if preventive measures and increasing immunity bring the effective reproduction number below one, Professor Britton says an outbreak will soon end. 

Hopes of building immunity

Professor Britton works with SIR models that map the number of people who are susceptible, infected and recovered. Chinese experts say patients with COVID-19 do develop a protective antibody – although it remains unclear how long that lasts and isolated cases of reinfection have been reported.

Evidence is also mounting that many people with coronavirus are only mildly affected. One new study suggests 17.9 per cent have no symptoms at all. For some, this stokes fears about the spread of an invisible disease. But the mathematician has a different perspective. “Essentially, that is good news because it means immunity will build up in the community quicker than we had thought,” he says.

Prof Tom Britton, Stockholm University/Photo by Konstantin Kriechbaum

Mathematical modelling of diseases starts with just a few basic parameters to understand fundamental trends. “As you make models more realistic, you add heterogeneities,” explains Professor Britton. This can make models more relevant to different societies. “For example, you divide the population into age groups and households and make assumptions about who has most contact with whom.”

Find out about opportunities to study at Stockholm University

Complete lockdowns that dramatically reduce personal contact can ensure an outbreak does not explode, as demonstrated in China, by bringing R well below 1. “But if you do it for two months and then go back to normal, coronavirus will come back,” warns Professor Britton, who is in contact with the Swedish Public Health Agency’s modelling team to offer suggestions several times per day. So, with the preventive steps taken, what does Professor Britton expect Sweden’s final rate of coronavirus infection to be?

“I think that eventually, say within a year, around 60 percent of us will get infected,” he says. “The importance lies in slowing it down so that it does not happen too quickly and overburden healthcare. I also think the fatality rate is smaller than initially expected, perhaps 0.2 to 0.4 percent.”

Fighting for the future

Amid warnings that COVID-19 could return annually, Stockholm University is carrying out research to develop an antiviral treatment for the coronavirus. The Fight-nCoV project is one of 17 being funded by European Union grants worth €47.5 million aimed at vaccine development, treatment and diagnostics. 

Anna-Lena Spetz, professor of immunology at the Department of Molecular Biosciences, The Wenner-Gren Institute, is leading the efforts to produce a new type of antiviral drug that would also fight other viruses that attack the upper airways. Developing a “broad-spectrum” antiviral treatment also means “building preparedness for future epidemics, when the next animal-human viral transmission occurs,” says Professor Spetz. 

Find out more about Stockholm University's EU grant for coronavirus research

Fight-nCoV will receive €2.8 million for two years of research. The Stockholm University team will work with colleagues in Sweden, Germany, Denmark and France to test the effect of drugs on the coronavirus in test tubes and animal models.

Chemists lend a helping hand in current healthcare crisis

In parallel to research being conducted at the University, solidarity actions and concrete help have also been part of researchers’ support in the current coronavirus crisis, for instance by Stockholm University’s chemists. The Swedish healthcare system is facing shortages of hand sanitiser and disposable protective equipment due to coronavirus.

Photo by Konstantin Kriechbaum/Stockholm University

Chemistry Department heads spoke to one hospital and were asked if they could manufacture hand sanitiser as the demand is currently very high. Chemists began collecting the ingredients for alcohol production and set to work. In next to no time, they had a consignment of over 200 litres of hand sanitiser, as well as plastic gloves, face masks and other items.

Danderyd Hospital in Stockholm was the first to collect vital supplies and more hand sanitiser continues to be produced, destined for Karolinska University Hospital in Huddinge. “This is teamwork where many people do a fantastic job,” says Berit Olofsson, a professor of organic chemistry and section dean about the initiative, which has now spread to several other universities in Sweden following Stockholm University’s example. 

This article was produced by The Local Creative Studio and sponsored by Stockholm University.


Sweden’s pandemic strategy ‘fundamentally correct’: Coronavirus Commission

Sweden's Covid-19 response was "fundamentally correct", but the government should have taken the lead, and brought in earlier and tougher measures, the country's Coronavirus Commission has concluded.

Sweden's pandemic strategy 'fundamentally correct': Coronavirus Commission

“It was fundamentally right to rely on issuing advice and recommendations,” Mats Melin, the commission’s chair said at a press conference after issuing the report. “The state should not limit the freedom of the individual more than is necessary to limit a dangerous sickness.” 

In addition, he noted, countries which had imposed greater restrictions had not necessarily had better outcomes. 

“We are not convinced that long-lasting and repeated lockdowns are necessary element in the response to a new, serious epidemic outbreak,” he said. 

Sweden made headlines early on in the pandemic by not introducing a lockdown, instead issuing recommendations on home-working, social distancing and good hand hygiene.

But tougher measures should have been introduced in February-March 2020, Melin said, with the measures that were imposed “too few” and coming “too late”. 


While the commission hailed Sweden’s decision to keep most schools open during the first wave, it said that by March 2020 there “should have been temporary closures” of indoor places where people gather, such as shopping centres, restaurants, sport events and so on.”

In particular, it criticised the fact that it took until the end of March 2020 for the limit on public gatherings to be lowered to 50 people. 

It also said that those returning from ski trips in Italy at the end of February and the start of March should have been asked to quarantine, while incoming travel should have temporarily been stopped for all but the most necessary journeys, as happened in Denmark and Norway.   

In an interview with The Local, Sweden’s health minister Lena Hallengren welcomed the commission’s conclusion that the fundamental strategy had been correct. 

“That the commission concludes that the overall strategy based on non-invasive recommendations and a non-lockdown policy, that they think that was the right choice. I think that’s good,” she said. 

At later stages of the pandemic, Sweden eventually introduced stricter measures, including bans on elderly home visits, earlier closings at bars and restaurants, and vaccine passes for indoor events.

The commission also said the government should have assumed leadership of all aspects of Covid crisis management, despite the Public Health Agency’s large degree of autonomy and a healthcare system managed by self-governing regional councils.

“The government had too one-sided a dependence on assessments made by the Public Health Agency”, it said.

It was not until the end of October that the government began to try to take a leading role, with documentation obtained by the commission showing the then Prime Minister Stefan Löfven trying to take more precedence over the Public Health Agency. 

The government, it concluded, should also have sought to get alternative views from other infectious disease and public health experts, rather than relying solely on the Public Health Agency’s expertise.   

Hallengren told The Local that she rejected this aspect of the report. 

“The government has been the one leading and deciding, and we are responsible,” she said. 

She also rejected the claim that the government had been over-reliant on the agency’s experts. 

“They can have their opinion about that, but the fact is, that the Public Health Agency is not an expert, it’s hundreds of experts, who are working with infection control and working with public health issues all the time,” she said. “It would be very strange if I, as minister for health, or the government, relied on specific or unique experts instead of this very big expert authority when it comes to epidemiological knowledge.”

An earlier partial report by the commission had also criticised the country’s slowness is setting up adequate testing measures.

With more than 17,000 fatalities so far, Sweden’s death toll is slightly better than the European average but is far higher per capita than those of neighbouring Norway, Finland and Denmark.