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Infection fatality risk for SARS-CoV-2 in community dwelling population of Spain: nationwide seroepidemiological study

BMJ 2020; 371 doi: (Published 27 November 2020) Cite this as: BMJ 2020;371:m4509

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Is the infection fatality rate for COVID-19 worse than that for influenza?

Dear Editor

Is the infection fatality rate for COVID-19 worse than that for influenza?

Pastor-Barriuso et al. found an infection fatality rate for COVID-19 of 0.8% in Spain (1). They quote an unpublished review that found 0.68%, with estimates ranging from 0.16% to 1.60% (2). In their discussion, they mention this review again: “Our overall estimate of infection fatality risk was similar to that found in seroepidemiological surveys with a low risk of bias.”

But what about other reviews? They quote in the introduction a 2020 review by John Ioannidis, which is in press in the Bulletin of the World Health Organization, (3) but do not say what he found, only that the magnitude of the infection fatality risk is being debated. Sure, but that is not informative.

Ioannidis included 61 studies (74 estimates) and eight preliminary national estimates. He reported that the infection fatality rates ranged from 0.00% to 1.63% and that the median rate was 0.27% (3).

Pastor-Barriuso et al. concluded that the infection fatality rate they found was about 10 times larger than those for seasonal influenza. They quoted the US Centers for Disease Control (4), but this agency may be a highly unreliable source when it comes to influenza (5).

Infection fatality rates for virus infections depend on the infectious dose (5), which is higher in settings with overcrowding. We can therefore only estimate death rates approximately. In outbreaks of measles, a commonly used estimate is 0.2%, but it can be many times higher. When measles hit a nonimmune population in the Faroe Islands in 1846, 78% were attacked and the case fatality rate was 2.8%, over 10 times higher than the usual rate of 0.2% (5, 6).

It is therefore not surprising that for influenza, as for all viral diseases, there are huge variations in reported case-fatality rates. In a systematic review, the median was about 1% for laboratory confirmed influenza during the mild influenza pandemic in 2009 and the following years (estimated by me from figure 3 in the paper) (7).

These data contradict the assertion by Pastor-Barriuso et al. that the infection fatality rate for COVID-19 is about 10 times larger than that for influenza. It seems to be about the same. In Denmark, when blood donors were tested for coronavirus antibodies, the death rate for COVID-19 was only 0.16% (8).

Pastor-Barriuso et al. concluded that their result supports existing measures, “e.g. social distancing, face masks, and educational campaigns.”

I disagree. The infection fatality rate seems to be about the same as for influenza, but we have never introduced these drastic measures before, when we had influenza pandemics. And we cannot live with them for years to come. The World Bank has just estimated that the corona pandemic has caused an increase of about 100 million people living in extreme poverty (9). This is not because of COVID-19. It is because of the draconian measures we have introduced. We need a better strategy.

1 Pastor-Barriuso R, Pérez-Gómez B, Hernán MA, et al. Infection fatality risk for SARS-CoV-2 in community dwelling population of Spain: nationwide seroepidemiological study. BMJ 2020;371:m4509ht.

2 Meyerowitz-Katz G, Merone L. A systematic review and meta-analysis of published research data on COVID-19 infection fatality rates. Int J Infect Dis 2020;101:138-48. doi:10.1016/j.ijid.2020.09.146.

3 Ioannidis J. Infection fatality rate of COVID-19 inferred from seroprevalence data. Bull World Health Organ (in press).

4 Centers for Disease Control and Prevention. Disease burden of influenza. 2020.

5 Gøtzsche PC. Vaccines: truth, lies and controversy. Copenhagen: People’s Press; 2020.

6 Panum PL. Observations made during the epidemic of measles on the Faroe Islands in the year 1846.

7 Ahmed F, Lindley M, Allred N, et al. Effect of influenza vaccination of healthcare personnel on morbidity and
mortality among patients: systematic review and grading of evidence. Clin Infect Dis 2014;58:50-7.

8 Jørgensen AS. Dødelighed skal formentlig tælles i promiller: Danske blodprøver kaster nyt lys over coronasmitten.
DR TV 2020; Apr 8.

9 COVID-19 to Add as Many as 150 Million Extreme Poor by 2021. World Bank 2010; Oct 7.

Competing interests: No competing interests

01 December 2020
Peter C Gøtzsche
Professor and director
Institute for Scientific Freedom, Copenhagen