2023-2024 Respiratory Disease Season Outlook - Previous Updates

CDC continues to anticipate this fall and winter respiratory disease season will likely result in a similar number of hospitalizations as last season. We have moderate confidence in this assessment, which is greater confidence than in our earlier assessments because current levels of respiratory disease activity are approaching peak levels reached last season.A We remain uncertain when activity will peak. We note that surveillance data, current forecasts, and growth estimates may be impacted by delays in reporting due to the holidays, which may add additional uncertainty to this month’s assessment. This assessment remains unchanged from our previously published respiratory season outlook, based on observed disease activity over the last month, COVID-19 and influenza forecasts, and past data for all three diseases.

• COVID-19 surveillance data, hospital admission forecasts, and growth estimates indicate that COVID-19 activity has increased and is likely to continue increasing into January. Although rates of hospitalization and Emergency Department visits due to COVID-19 are currently lower than this time last season, COVID-19 remains the primary cause of respiratory virus-associated hospitalizations nationally. We continue to track variants of COVID-19, including the JN.1 variant. While JN.1 is now the most widely circulating variant in the United States, the spread of JN.1 does not lead us to change our assessment.

• Influenza surveillance data, hospital admission forecasts, and growth estimates indicate that influenza activity has increased and is likely to continue increasing into January. Cumulative influenza hospitalization rates are similar to rates observed at this time during several pre-COVID-19-pandemic seasons, including the high-severity 2017-18 season. Influenza is now the primary cause of Emergency Department visits for viral respiratory diseases nationally.

• RSV activity remains elevated nationally and continues to increase in many areas of the country, though sustained decreases have been observed for the past few weeks in Southeastern states. The national per capita hospitalization rate remains lower than the peak for last season.

We continue to monitor for signs that the respiratory disease season could be worse than expected, such as an unusually severe influenza season, the coincidence of multiple respiratory disease peaks, or the emergence of a COVID-19 variant that causes more severe illness.

Vaccination remains the best way to protect yourself and your loved ones against serious outcomes of these viral respiratory illnesses. Vaccination is especially important for people at increased risk for severe disease, including infants, older adults, pregnant people, and people with certain underlying medical conditions.

• As of January 5, 2024, the percent of the population reporting receipt of the updated COVID-19 vaccine remains very low for children (8.0%) and adults (19.4%).

• As of January 5, 2024, the of the population reporting receipt of this season’s influenza vaccine remains low for children (43.9%) and adults (44.9%).

• RSV vaccine uptake also is low among older adults and pregnant people, the two groups of people who may get one dose of this vaccine. CDC recommends that infants be protected from RSV through an RSV vaccine given to the mother during weeks 32-36 of pregnancy or immunization through an RSV preventive antibody given to infants.

There are other actions you can take to protect yourself and others from viral respiratory illnesses. Learn about how to reduce your risk of getting sick from these viruses.

CDC continues to anticipate this fall and winter respiratory disease season will likely result in a similar number of hospitalizations as last season. While this number could be somewhat higher or lower than last season, the United States most likely will see greater hospitalizations than in seasons before the pandemic. This assessment remains unchanged from our previously published respiratory season outlook, based on observed disease activity over the last month, COVID-19 and influenza forecasts, and past data for all three diseases. We have low to moderate confidence in this assessment, due to uncertainties anticipating the timing and levels of peak disease activity this early in the season.

• Influenza surveillance data and hospital admission forecasts indicate that influenza activity has increased and is likely to continue increasing into December.

• Most parts of the country are experiencing elevated RSV activity, and these increases in disease activity are happening slightly earlier than in pre-pandemic years, but later than the past two pandemic seasons. However, the growth in new RSV hospitalizations nationally is less steep than last year, indicating that a lower and later peak is likely at a national scale.

• COVID-19 activity has modestly increased in some areas of the country since our last update, and it remains the cause of most new respiratory virus hospitalizations and deaths. COVID-19 variants continue to emerge but have not resulted in recent rapid disease surges.

• We continue to monitor for signs that the respiratory disease season could be worse than expected, such as an unusually severe influenza season, the coincidence of multiple respiratory disease peaks, or the emergence of a COVID-19 variant that spreads more quickly or effectively.

Vaccination remains the best way to protect yourself and your loved ones against serious outcomes of these viral respiratory illnesses. Vaccination is especially important for people who are at higher risk of developing serious complications, particularly as respiratory disease activity is increasing.

CDC continues to anticipate that the upcoming fall and winter respiratory disease season will likely result in a similar number of hospitalizations as last season. While this number could be somewhat higher or lower than last season, the United States most likely will see greater hospitalizations than in seasons before the pandemic. This assessment remains unchanged from our previously published respiratory season outlook, based on observed disease activity over the last month and other new information. We continue to have low-to-moderate confidence in this assessment due to uncertainties anticipating the timing and levels of peak disease activity.

• As of October 20th, respiratory virus activity is low nationally. COVID-19 activity continues to decline in many areas of the country but remains the cause of most new respiratory virus hospitalizations and deaths. Sustained increases in RSV activity in the southern U.S. indicate the start of the 2023-2024 RSV season, with the mid-Atlantic and Northeastern regions also now experiencing elevated activity. Influenza activity remains low in most areas of the country, but small increases were reported in some places. COVID-19 variants continue to emerge but have not resulted in rapid disease surges. Currently we do not have evidence that the BA.2.86 variant is driving increases in infections or hospitalizations in the United States. We continue to anticipate a moderate COVID-19 wave, causing around as many hospitalizations at the peak as occurred at last winter’s peak.

• According to recent influenza modeling by the Scenario Modeling Hub, influenza hospitalizations are likely to fall within the range observed from 2010 – 2020, which is consistent with our season outlook for influenza. Modeling results indicate that a 20% relative increase in vaccine coverage across age-groups compared to recent seasons could avert around 9% of influenza-associated hospitalizations this season. Conversely, a 20% drop in relative vaccine coverage could increase influenza-associated hospitalizations at least 10%.

• RSV activity remains in line with normal seasonal patterns prior to the emergence of COVID-19 consistent with our season outlook for RSV.

Vaccination remains the best way to protect yourself and your loved ones against serious outcomes of these diseases. Vaccination is especially important for people who are at higher risk of developing serious complications.

CDC will continue to monitor respiratory virus activity and update this outlook as we learn more. Get the latest on influenza, COVID-19, and RSV disease activity here.