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The 2024 holiday season saw a surge in respiratory virus spread, underscoring the ongoing need for holiday-related virus transmission assessment and prevention.

The holiday season is often associated with joyful giving, but one unwelcome “gift” is the transmission of respiratory viruses.  

The Centers for Disease Control and Prevention (CDC) provides weekly in-season disease burden reports based on laboratory-confirmed COVID-19-, respiratory syncytial virus (RSV)-, and influenza-associated hospitalizations from a network of hospitals covering approximately 10% of the US population. Preliminary 2024-25 US burden estimates revealed the following: 

• From October 1, 2024, to December 14, 2024, COVID-19 resulted in 2.7-4.9 million illnesses, 670,000-1.1 million outpatient visits, 78,000-130,000 hospitalizations, and 8,900-15,000 deaths. 
• From October 1, 2024, to December 14, 2024, RSV led to 590,000-1.2 million outpatient visits, 29,000-60,000 hospitalizations, and 1,300-31,000 deaths.  
• From October 1, 2024, to December 21, 2024, influenza caused 3.1-5.4 million illnesses, 1.4-2.5 million medical visits, 37,000-76,000 hospitalizations, and 1,500-7,200 deaths. 

Reports indicated rising incidents as the holiday season progressed. As of December 27, 2024, the CDC reported that acute respiratory illness levels remained high nationally. These trends underscore the need to continue assessing holiday-related virus transmission and developing proactive measures to mitigate its impact. 

Holiday-Related Virus Transmission: Assessments & Advice 

Recent studies have analyzed the holiday-related increase in respiratory virus transmission and provided strategies for reducing spread: 

• A 2024 Epidemiology and Health study examined the extent of increased COVID-19 transmission frequency during public holidays in Japan. Researchers modeled incidence and mobility data across four prefectures, finding that reproduction numbers rose by 3.19%-24.82%, resulting in 580-5,211 additional cases linked to holiday periods. “Public holidays intensified the transmission of COVID-19, highlighting the importance of considering public holidays in designing appropriate public health and social measures in the future,” Hiroshi Nishiura, MD, and Jiaying Qiao concluded. 
• Likewise, a 2023 Scientific Reports–published study highlighted New Year’s Eve celebrations as a trigger for SARS-CoV-2 surges among Belgian students. Researchers found a sharp rise in Omicron BA.1 cases attributed to gatherings despite social restrictions. “Overall, our results indicate that, even under social restrictions, a surge in transmissibility of SARS-CoV-2 can occur when holiday celebrations result in small social gatherings attended simultaneously and communitywide,” Caspar Geenen and colleagues reported. 
• To better understand how human mobility and infectious disease epidemics interact, a 2023 Infectious Disease Modelling-published study employed a modified susceptible-exposed-infectious-recovered epidemiological model to simulate various COVID-19 outbreak scenarios during the holiday season, incorporating both inter-regional and intra-regional human mobility effects into the parameterization scheme. For China, the findings revealed a 57.35% surge in cases due to intra-city mobility and a 15.18% rise from inter-city mobility. The US simulation revealed that human mobility played a more pronounced part in the outbreak, with a notable disparity in peak cases when mobility was considered. “This study highlights that while inter-regional mobility acted as a trigger for the epidemic spread, the diffusion effect of intra-regional mobility was primarily responsible for the outbreak,” Han Li and colleagues concluded. 
• In an Influenza and Other Respiratory Viruses–published study, researchers in Canada examined the relationship between cough-related ED visits [defined as influenza-like illness (ILI)] and laboratory detections for influenza A and RSV, comparing Christmas-New Year holiday volumes to non-holiday volumes during the influenza season. “During non-pandemic years, the highest peak in ILI-related visit volumes always occurred during the holidays,” Leah Martin-Visscher, PhD, and colleagues stated. “This predictability should be used to prepare for, and possibly prevent, this increase in healthcare use; however, interventions beyond disease prevention strategies are likely needed.” 

New Year, New Opportunities 

While the 2024 U.S. holiday season is nearing its end, clinicians treating patients infected during the 2024 holidays have a timely opportunity to provide reminders for avoiding infections next holiday season. Recommendations from the Infectious Diseases Society of America include: 

• Staying current on vaccinations, reminding friends and family to do the same, and encouraging timely immunization at least two weeks before gatherings; 
• Wearing masks when using public transportation; 
• Washing hands with soap and water at key moments upon arrival at a gathering, before preparing food, and before and after eating; and 
• Considering pre-gathering testing to reduce infection risks. 

Looking Ahead

Improved understanding of seasonal virus trends can drive the development of proactive strategies to curb holiday-related virus transmission, contributing to healthier future holidays for all. 

Want to learn more about holiday-related health issues? Read our articles on how the holiday season impacts cardiac health, digestive health, and clinician work stress!