Virus World

In the current COVID-19 pandemic a key unsolved question is the duration of acquired immunity in recovered individuals. The recent emergence of SARS-CoV-2 precludes a direct study on this virus, but the four seasonal human coronaviruses may reveal common characteristics applicable to all human coronaviruses.

We monitored healthy subjects over a time span of 35 years (1985-2020), providing a total of 2473 follow up person-months, and determined a) the time to reinfection by the same seasonal coronavirus and b) the dynamics of coronavirus antibody depletion post-infection. An alarmingly short duration of protective immunity to coronaviruses was found. Reinfections occurred frequently at 12 months post-infection and there was for each virus a substantial reduction in antibody levels as soon as 6 months post-infection.

Preprint Available (June 16, 2020):

https://doi.org/10.1101/2020.05.11.20086439

Article published in Nat. Medecine (Sept. 14, 2020):

https://doi.org/10.1038/s41591-020-1083-1

An analysis of four different coronaviruses over an 8-year period demonstrated that they were detected in a limited timeframe, from December to April and May, with a peak during January and February, according to a recent study published in Journal of Infectious Diseases. “This is part of a continuing study in families first designed to examine how the influenza vaccine is working in the community,” Arnold S. Monto, MD, Thomas Francis, Jr. Collegiate Professor of Public Health at the University of Michigan School of Public Health, told Healio. “We have expanded it to look broadly at all respiratory viruses.”

The four coronaviruses in the study are known to cause respiratory infections every year, according to Monto: “We had these data ready to go when the pandemic started.” Acute respiratory infections have been identified in children and adults aged 8 years and older as part of the Household Influenza Vaccine Evaluation study. Researchers obtained specimens from 890 to 1,441 individuals in Michigan, who they followed and contacted weekly in order to obtain information about acute respiratory infections. Specimens were tested for four coronavirus types: OC43, 229E, HKU1 and NL63.

Over the 8-year study period, 993 coronavirus infections were detected. The most common type was OC43 and 229E was the least common. The study showed that the coronaviruses were identified during a limited time period, from December to April/May, with a peak recorded in January or February. The viruses began to diminish in March.

Study Published in J. Infect. Diseases (April 4, 2020):

 https://doi.org/10.1093/infdis/jiaa161