A first look at the trends following most winter holidays shows that seasonal virus activity remains high and continues to rise across the United States, according to data from the US Centers for Disease Control and Prevention. As infections and hospitalizations increase, the Centers for Disease Control and Prevention continues to stress the importance of vaccination — and the value of treatment to avoid severe illness.
Overall, influenza-like activity is high or very high in all but a dozen states. Multiple indicators, including test positivity, emergency department visits and hospitalizations, are elevated for respiratory viruses including Covid-19, influenza and respiratory syncytial virus.
Respiratory syncytial virus activity has shown signs of slowing in some parts of the province, especially in the south, but coronavirus and influenza activity is increasing in most parts of the country. Covid-19 viral activity in wastewater is the highest in the Midwest, and nationally, and higher than it has been for most of the pandemic.
Weekly hospitalization rates for respiratory viruses have been rising for about three months, since early October. In the last week of 2023 — through Dec. 30 — there were nearly 35,000 new admissions for Covid-19 and more than 20,000 new admissions for influenza, according to CDC data. Hospitalizations for Covid-19 were up about 20% and hospitalizations for influenza were up about 36% compared to the previous week.
For most of December, influenza brought more people to the emergency department than coronavirus, but coronavirus still accounts for most hospital admissions associated with respiratory viruses.
The JN.1 variant, which now accounts for more than three in five new Covid-19 infections, “may intensify the spread of COVID-19 this winter,” the CDC said in a blog post on Friday. While coronavirus hospitalizations and deaths are lower than they were at this time last year, infection levels — measured by wastewater and positive test metrics — are higher.
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Vaccination can help prevent serious illness, including hospitalization or death, and broader population immunity — from vaccination, previous infection, or both — helps prevent a smaller percentage of infections from becoming severe, according to the Centers for Disease Control and Prevention. Of which. But immune protection can fade over time, hence the need for updated annual doses.
However, vaccination rates remain low among both children and adults. As of December 30, less than half of adults and children have received the seasonal influenza vaccine. Only about 19% of adults and 8% of children have gotten the latest COVID-19 vaccine, and only 18% of older adults have gotten the new respiratory syncytial virus vaccine.
However, vaccination cannot prevent all infections, and antiviral treatments are available for those who become ill and are at risk of severe disease. But “not enough people are taking them,” according to the CDC.
“If more people at high risk of serious illness get timely treatment, we will save lives,” the agency said in a blog post last month.
Research shared as a preprint online this summer found that less than 10% of people who became infected with Covid-19 between December 2021 and February 2023 got a prescription for baxlovid. If this had increased to half of eligible patients receiving treatment, about 135,000 hospitalizations and 48,000 more deaths could have been prevented.
“This underscores the need to improve uptake of effective interventions for COVID-19,” the researchers wrote.
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There are also four antiviral medications available to treat influenza. As with COVID-19 treatments, flu treatments are recommended for people most at risk of flu complications, including young children, adults 65 and older, pregnant women and people with certain medical conditions such as asthma, diabetes and heart disease.
Testing is not required to start antiviral treatment. The CDC says starting treatment as soon as possible is important, and it may not make sense to wait for test results. But testing can ensure the right course of treatment is being used and help patients avoid spreading the virus.
For now, the CDC says hospital bed occupancy remains stable nationwide. But the agency expects this respiratory virus season to cause a similar number of hospitalizations as last season.