Summer cold? Viruses return post-pandemic.
In certain regions of the United States this summer, colds have made a vigorous comeback after receding during the pandemic.
Disease experts suggest that rhinoviruses, which are the primary culprits behind common cold infections, circulate throughout the year. However, gatherings during the summer season, such as weddings, barbecues, and graduations, may have expedited their transmission.
Dr. Michelle Barron, senior medical director of infection prevention and control at UCHealth in Colorado, remarked on the prevalence of rhinovirus during the summer, stating, “It’s remarkable how much you encounter it in this season.”
Additionally, the country is witnessing a significant increase in adenovirus infections, according to data from the Centers for Disease Control and Prevention (CDC). Adenoviruses typically cause mild respiratory illnesses characterized by symptoms like fever, sore throat, pink eye, diarrhea, and skin rashes.
Kathleen Conley, a public affairs specialist at the CDC, mentioned that respiratory adenovirus activity has been steadily rising since the summer of 2021 compared to earlier in the pandemic. The current activity levels exceed those of the same period in 2022, although they seem to be stabilizing.
Conley added that adenovirus activity “remains within the range expected for this time of year,” and many other respiratory viruses have also returned to pre-pandemic levels. She noted that earlier this year, several of these viruses reached levels similar to those observed before 2020.
Data from the Seattle Flu Study, which monitors the prevalence of respiratory illnesses among individuals with symptoms in King County, Washington, indicates a notably high number of adenovirus cases this summer.
In early June, approximately 25% of symptomatic individuals in the study who tested positive for a respiratory pathogen were infected with adenovirus. This percentage surpassed the peak observed in the summer of 2019 (17%) and far exceeded the levels recorded in 2020, 2021, and 2022.
Dr. Ana Weil, a principal investigator at the Seattle Flu Alliance and an assistant professor of allergy and infectious diseases at the University of Washington School of Medicine, stated, “There is definitely a higher prevalence of adenovirus at the moment compared to the usual.”
According to the Seattle Flu Study, rhinovirus accounted for 33% of symptomatic respiratory illnesses in King County in early June, aligning with pre-pandemic levels.
In the study, Covid-19 represented only 2% of symptomatic respiratory illnesses. Although the CDC no longer tracks Covid-19 cases, hospitalizations have steadily declined since the beginning of the year. As of mid-June, the CDC recorded fewer than 6,400 new weekly Covid-19 hospitalizations, a significant drop from the more than 44,000 reported in early January.