Flu Vaccination Among Hospital Health Care Workers Fell During the COVID-19 Pandemic

Health care personnel in U.S. acute care hospitals became less likely to get a flu shot during the COVID-19 pandemic. Coverage rose from 88.6% in 2017–18 to 90.7% in 2019–20, then fell to 85.9% in 2020–21, 80.4% in 2021–22 and 81.1% in 2022–23, according to a CDC analysis.

Why it matters

Health care personnel can catch flu, miss work, and pass the virus to patients and co-workers. The Advisory Committee on Immunization Practices recommends that they be vaccinated every year to reduce flu illness and death.

The data

Since 2013, the Centers for Medicare & Medicaid Services has required acute care hospitals to report, every year, how many of their staff who worked at least one day from October 1 to March 31 received a flu vaccine, to CDC's National Healthcare Safety Network (NHSN). Reporting was made optional for 2019–20 to ease hospitals' workload in the pandemic.

CDC analysed six seasons, 2017–18 to 2022–23, from 5,231 hospitals (2,908, or 55.6%, reported in the optional 2019–20 season). It counted 2019–20 as pre-pandemic, since flu shots are mostly given by January and widespread COVID-19 transmission began only in March 2020. It compared the periods while accounting for type of worker and whether the hospital was urban, suburban or rural.

Results

Over the six seasons, coverage was 85.8%.

• Workers were significantly less likely to be vaccinated in the pandemic seasons than in 2017–18.
• Licensed practitioners not employed by the hospital, such as affiliated physicians, advanced practice nurses and physician assistants, were much less likely to be vaccinated than employees (odds ratio 0.35), as in earlier years.
• Workers in suburban hospitals were more likely to be vaccinated than those in rural ones; urban and rural did not differ.

Possible reasons

The authors suggest several. Elsewhere in the world, similar declines have been linked to COVID-19 vaccination campaigns drawing attention from flu vaccination and to fatigue after several COVID-19 doses. Some workers may have hesitated to get both vaccines at once, although giving them together is safe and effective. And with masks worn throughout facilities and fewer flu cases, hospitalisations and deaths in 2020–21 and 2021–22, flu at work may have seemed less of a risk and the vaccine less important.

Hospitals can reach their own employees more easily, for example with free vaccination, and facility vaccine mandates raise coverage, but mandates may be hard to enforce among practitioners they don't employ.

Limitations

• Hospitals report on their staff's behalf, which may miss shots received elsewhere, especially by non-employees.
• The data are totals per facility, so they cannot be broken down by age, race or ethnicity.
• Only some hospitals reported in 2019–20.
• NHSN does not record hospitals' vaccine mandates, so their effect could not be judged.

What hospitals can do

Annual vaccination protects both staff and patients. Hospitals can use proven strategies: mandatory vaccination policies and free on-site vaccination for all staff, employees or not. Understanding what drove the recent decline could help target efforts in future emergencies.

Sources

• Lymon H, Meng L, Reses HE, et al. "Declines in Influenza Vaccination Coverage Among Health Care Personnel in Acute Care Hospitals During the COVID-19 Pandemic — United States, 2017–2023," MMWR. https://www.cdc.gov/mmwr/volumes/72/wr/mm7245a6.htm