The Centers for Disease Control and Prevention (CDC) is issuing this Health Alert Network (HAN) Health Advisory about early, elevated respiratory disease incidence caused by multiple viruses occurring especially among children and placing strain on healthcare systems. Co-circulation of respiratory syncytial virus (RSV), influenza viruses, SARS-CoV-2, and others could place stress on healthcare systems this fall and winter. This early increase in disease incidence highlights the importance of optimizing respiratory virus prevention and treatment measures, including prompt vaccination and antiviral treatment, as outlined below.
Many respiratory viruses with similar clinical presentations circulate year-round in the United States and at higher levels in fall and winter. In the past 2 years, respiratory disease activity has been dominated by SARS-CoV-2, and seasonal circulation of other respiratory viruses has been atypical or lower than pre-COVID-19 pandemic years. Currently, the U.S. is experiencing a surge and co-circulation of respiratory viruses other than SARS-CoV-2. CDC is tracking levels of respiratory syncytial virus (RSV), influenza, and rhinovirus/enterovirus (RV/EV) that are higher than usual for this time of year, especially among children, though RV/EV levels may have plateaued in recent weeks. SARS-CoV-2 also continues to circulate in all U.S. states.
CDC surveillance has shown an increase in RSV detections and RSV-associated emergency department visits and hospitalizations in all but two U.S. Department of Health and Human Services (HHS) regions (regions 4 and 6), with some regions already near the seasonal peak levels typically observed in December or January. This year, rates of RSV-associated hospitalizations began to increase during late spring and continued to increase through the summer and into early fall. Preliminary data from October 2022 show that weekly rates of RSV-associated hospitalizations among children younger than 18 years old are higher than rates observed during similar weeks in recent years. While RSV activity appears to be plateauing in some places, the timing, intensity, and severity of the current RSV season are uncertain.
CDC has been tracking early and increasing influenza activity in recent weeks. The highest levels of influenza activity have been found in the southeast and south-central parts of the country. The most common viruses identified to date have been influenza A(H3N2) viruses, with most infections occurring in children and young adults. Cumulative influenza-associated hospitalization rates for children (age 0–4 years and 5–17 years) and all ages combined are notably higher compared to the same time periods during previous seasons since 2010–2011. Although the timing, intensity, and severity of the 2022–2023 influenza season are uncertain, CDC anticipates continued high-level circulation of influenza viruses this fall and winter.
CDC data are available to monitor COVID-19 community levels, which are based on hospitalization and case data and can be used to track SARS-CoV-2 activity. SARS-CoV-2 activity is expected to increase in the winter as has been observed in previous years. Rates of COVID-19-associated hospitalizations among all age groups including children have decreased since August, but rates in infants younger than 6 months remain higher than in other pediatric age groups and higher than in all adult age groups except those 65 years and older. CDC expects continued high-level circulation of SARS-CoV-2 this fall and winter.
Recommendations for Healthcare Providers
CDC recommends that healthcare providers offer prompt vaccination against influenza and COVID-19 to all eligible people aged 6 months and older who are not up to date. Vaccination can prevent hospitalization and death associated with influenza and SARS-CoV-2 viruses.
Influenza vaccines have been updated for the current season (1). Of influenza A(H3N2) viruses that have been analyzed in the United States since May 2022, most A(H3N2) viruses are genetically and antigenically closely related to the updated A(H3N2) vaccine component. These data suggest influenza vaccination this season should offer protection against the predominant A(H3N2) viruses to date.
Currently approved SARS-CoV-2 bivalent mRNA booster doses for use in patients 5 years of age and older offer protection against both the ancestral SARS-CoV-2 virus and the currently predominant Omicron BA.4 and BA.5 subvariants that cause COVID-19. Emerging evidence suggests that COVID-19 vaccination provides some protection against multisystem inflammatory syndrome in children (MIS-C) and against post-COVID-19 conditions, and that vaccination among persons with post–COVID-19 conditions might help reduce their symptoms (2).
To prevent RSV-associated hospitalizations, eligible high-risk children should receive palivizumab treatment in accordance with AAP guidelines. In brief, children eligible for palivizumab include infants prematurely born at less than 29 weeks gestation, children younger than 2 years of age with chronic lung disease or hemodynamically significant congenital heart disease, and children with suppressed immune systems or neuromuscular disorders.
While vaccination is the primary means for preventing influenza and COVID-19, antiviral medications are important adjuncts used to treat illness in persons with severe illness and those at increased risk for complications. Both influenza and COVID-19 antiviral medications are most effective in reducing complications when treatment is started as early as possible after symptom onset.