A barrage of criticism has led Jonas Ludvigsson of the Karolinska Institute to stop COVID-19 research.
Alexander Donka
By Gretchen Vogel
Science‘COVID-19 reporting is supported by the Heising-Simons Foundation.
The pediatrician and epidemiologist Jonas Ludvigsson of the Karolinska Institute in Sweden was a strong defender of his country’s unorthodox coronavirus policy. Among them was the decision in the spring of 2020 to keep preschools and schools open to children up to grade nine, despite the limited understanding of the virus and with few precautions to prevent school outbreaks. But Ludvigsson’s research, which suggests that the policy was relatively secure – and was widely quoted in arguments against school closures – has repeatedly come under criticism from Sweden’s approach.
The latest example is a research letter sent online by The New England Journal of Medicine (NEJM) on 6 January, which looked at serious illnesses and deaths among children and teachers in Sweden between March and June 2020. Critics – including the authors of two letters NEJM published March 1 – said the study was extraordinary and a distraction. It is known that children are less likely to be hospitalized or die of COVID-19; instead, schools worldwide have closed to slow the spread of the virus in the wider community.
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But Science heard that another complaint to NEJM makes a more serious assertion: that the authors deliberately omitted important data that contradicted their conclusion.
The complaint comes from Bodil Malmberg, a private citizen in Vårgårda, Sweden. She used the country’s law on public records to obtain e-mail correspondence between Ludvigsson and Swedish chief epidemiologist Anders Tegnell, the architect of the country’s pandemic policy, which sheds light on how the newspaper originated. Malmberg says she requested the email because the data in the NEJM paper “did not add.” Ludvigsson does not dispute the content of the email, but stands by the conclusions of the study. However, he says the criticism and personal attacks made him decide to stop using COVID-19 research.
Ludvigsson, whose prepandemic research focused on gastroenterology, was one of the 47 original signatories to the Great Barrington Declaration, a controversial document published in October 2020, arguing that pandemic policies should focus on protecting the vulnerable. while the rest of the population builds up immunity through natural infection.
Ludvigsson’s research apparently supports these ideas. In a review on the role of children in the pandemic, published in Acta Pediatrics in May 2020 he reported that there had been ‘no major school outbreaks in Sweden’, which he attributed to ‘personal communication’ from Tegnell. But as critics noted, the Swedish media at the time had already reported several school outbreaks, including one in which at least 18 of the 76 staff were infected and one teacher died. (Children have not been tested.)
His NEJM letter sounds another reassuring note. Between March and June 2020, it was reported that only 15 children, 10 preschool teachers and 20 school teachers were admitted to the intensive care units due to COVID-19 complications. The authors noted that 69 children aged 1 to 16 years to any cause in Sweden during the same period, compared to 65 between November 2019 and February 2020, indicating that the pandemic did not lead to an increase in child deaths.
But the emails Malmberg received show that Ludvigsson wrote to Tegnell in July 2020: ‘Unfortunately, we see a clear indication of excessive mortality among children aged 7 to 16, at the ages where’ children went to school. ‘up to and including 2019, an average of 30.4 children in the age group died in the four spring months; in 2020, 51 children in that age group will die, “= excessive deaths + 68%,” Ludvigsson wrote. The increase could be a surge, he wrote, especially since the numbers are small. Mortality in 1- to 6-year-olds was below average in the same period, and the combination of the age groups helped the increase, he noted.
The e-mails “cast a serious shadow on the research letter, Malmberg writes in an e-mail NEJM. (The magazine did not want to comment on her complaint.) Epidemiologist Jonas Björk from Lund University agrees that the time comparison used in the newspaper was unusual. “I can see no good reason to compare with previous months,” he says. “It is standard to compare with the same period in previous years” to offset the seasonality and reduce the statistical uncertainty.
Ludvigsson tells Science a peer reviewer for NEJM suggested the comparison with deaths in November to February, and that he summarized the numbers for preschool and school children as a result of the number NEJMlength requirements. As part of his March 1 response to the published criticism, he updated the supplementary data of the paper with the monthly deaths from 2015 to 2020, but did not notice the 68% increase in school-going children.
The increase in mortality is probably not simply due to COVID-19, Björk notes. Although Sweden tested very few children in the early months of the pandemic, fatal cases of COVID-19 would probably have appeared somewhere in the healthcare system. “This should, of course, be ruled out by investigating more causes of death and medical records,” he says. And Björk agrees that the increase may be due to coincidence.
The death toll sets aside, critics say the NEJM letter was just not very helpful in the heated debate over school closures. The biggest concern is not that children could end up in intensive care, but that schools could accelerate the spread of the community, says Antoine Flahault, a global health expert at the University of Geneva and co-author of one of the critiques in NEJM. Nisha Thampi, a physician for infectious children at the CHEO Pediatric Health and Research Center in Ottawa, Canada, agrees. The newspaper does not tell me much about what happens to children in schools, she says.
The arguments over whether schools are ‘safe’ have delayed efforts to find ways to reduce the risk of viral spread in classrooms and corridors, says Flahault – who is the key to keeping schools open and the virus beneath to control.