8-year study shows coronaviruses have ‘sharp seasonality’
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.
“The seasonal similarity between the 4 types is striking, with only the peak aggregate month differing between January and February,” the authors wrote.
The highest infection frequency occurred in children aged younger than 5 years, with 20% of cases in children being associated with medical consultation compared with 9% of adult cases. Slightly more than a quarter of infections (260/993) were acquired from a member of the household who was infected.
“These viruses seem to behave in some ways like other respiratory viruses, with the highest rates of infection occurring in young children,” Monto told Healio. “However, the infection rates are mainly level as age increases, which is somewhat unusual.”
These coronaviruses appear to be “sharply seasonal,” according to the study results. In addition, the transmission potential appears to be similar to that of influenza A(H3N2) in the same population.
“Although these viruses are related virologically to the COVID-19 virus, they mainly cause mild diseases. It is impossible to say whether their sharp seasonality in any way will also be seen with the pandemic virus,” Monto concluded. “This adds to the many questions now being considered about how the current pandemic will evolve.” – by Caitlyn Stulpin
Disclosure: Monto reports no relevant financial disclosures.