Flu season activity across the United States is currently low, but health officials express concern about potential challenges in the coming months. According to the U.S. Centers for Disease Control and Prevention (CDC), flu activity as of last week was classified as high in four states: Colorado, Louisiana, New Jersey, and New York. In contrast, most other states reported minimal or low levels of flu activity, indicating a relatively mild season so far.
This winter, various respiratory viruses, including influenza, norovirus, and respiratory syncytial virus (RSV), are being monitored closely by health experts. While the flu typically peaks around February, the current situation raises questions about the potential severity of the season, especially given last year’s particularly harsh flu epidemic, which saw the highest hospitalization rate since the H1N1 pandemic in 2009. That season also recorded 288 child flu deaths, marking it as one of the worst in recent history.
Health officials are particularly attentive to the A H3N2 flu virus, which has historically caused increased hospitalizations and fatalities among older populations. This season, A H3N2 has been the most frequently reported strain. Alarmingly, 89% of analyzed H3N2 infections are of a newer variant, known as the subclade K variant, which differs from the strain included in this year’s flu vaccines.
The CDC continues to recommend annual flu vaccinations for everyone aged six months and older, emphasizing that it is not too late to get the shot. As of now, about 42% of U.S. adults and 41% of children have received their flu vaccinations this season. Although the vaccine may not prevent all symptoms, it significantly reduces the risk of severe illness, as preliminary analyses from the United Kingdom suggest.
RSV and COVID-19 Trends
Respiratory syncytial virus, a common cause of cold-like symptoms, poses particular risks to infants and the elderly. Traditionally, RSV seasons peak by December or January, but the CDC reports that current RSV cases have been relatively low. Experts, including Dr. Cameron Wolfe from Duke University, speculate that RSV cases may still rise, particularly in southern and mid-Atlantic states.
The introduction of new RSV vaccines, approved in 2023 for pregnant women and older adults, may be contributing to improved vaccination rates. As of October, approximately 41% of Americans aged 75 and older have been vaccinated, along with about 40% of infants.
COVID-19 indicators have also shown a decline since the summer peak. The CDC recently published research indicating that COVID-19 vaccines can effectively prevent severe illness in children. Among children aged nine months to four years, the vaccine was found to be 76% effective in preventing severe symptoms requiring emergency care. For children aged five to seventeen, the effectiveness rate stood at 56%.
Despite the proven efficacy of COVID-19 vaccines, uptake has been low this season, with only about 7% of children and 15% of adults receiving the latest version. The CDC has recently shifted its stance, no longer recommending COVID-19 vaccinations for all individuals, leaving decisions to patients and their families. This change has sparked debate among various medical organizations advocating for continued vaccination efforts against a virus responsible for over 1.2 million deaths in the U.S.
The health landscape as winter approaches remains complex, with respiratory viruses poised to spread in indoor settings. As health officials continue to monitor flu, RSV, and COVID-19, the importance of vaccination and awareness remains paramount in mitigating the impact of these seasonal illnesses.
