In late March 2020, researchers from the Institut Pasteur conducted an epidemiological and serological study on 661 individuals connected to a high school in Crépy-en-Valois, Oise—one of France's earliest COVID-19 hotspots. What are the key takeaways?
Published results from France's inaugural sero-epidemiological investigation, led by the Institut Pasteur with support from the ARS des Hauts-de-France, Académie d'Amiens, and Établissement Français du Sang, targeted Oise department. The objective: accurately determine the proportion of people infected with COVID-19.
Conducted March 30 to April 4, the study involved 661 participants—students, parents, siblings, teachers, and staff—who completed questionnaires on fever or respiratory symptoms since January 13, 2020. Blood samples tested for SARS-CoV-2 antibodies.
Findings show 26% of participants developed SARS-CoV-2 antibodies. Attack rates reached 41% among high school attendees and 11% among their close contacts; just 5.3% required hospitalization.
Infection rates were similar across genders. School holidays starting February 14 and local containment from March 1 significantly slowed viral spread.
"These results inform public health strategies and outbreak surveillance," notes Arnaud Fontanet, Head of the Institut Pasteur's Emerging Diseases Epidemiology Unit. However, "observed attack rates indicate herd immunity won't emerge rapidly," particularly outside heavily affected areas.
Seroprevalence differed by smoking status, aligning with emerging research: 28% of non-smokers vs. 7.2% of smokers tested positive.
Nicotine may play a role, per some experts, but Public Health France stresses smoking offers no protection against COVID-19. Health Director General Jérôme Salomon warned non-smokers against nicotine patches due to risks like vomiting, dizziness, and addiction.
A recent decree limits nicotine replacement sales to one-month supplies until May 11, tracks dispensing, and suspends online sales.
Still, Institut Pasteur researchers suggest exploring nicotine's potential for COVID-19 prevention or treatment.
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