Takeaways From a 10-Year Mandatory Influenza Vaccine Program for Health Care Workers

Influenza activity in the United States remains elevated above the national baseline as flu season winds down. The key to avoiding infection lies with the flu shot, which reduces the risk of illness by 40 to 60% among the overall population, according to recent studies.

The Children’s Hospital of Philadelphia (CHOP) implemented a mandatory influenza vaccine policy 10 years ago for all health care employees unless they had a medical or religious exemption. Investigators conducted a post-mortem on the policy to help frame future efforts and to explore the barriers that exist in implementation. Their findings were presented at the Society for Healthcare Epidemiology of America Spring Conference (SHEA 2019).

Using 15 years’ worth of de-identified data from the CHOP Occupational Health Department, along with descriptive statistics, the research team calculated the annual rate of health care worker immunization (total number of vaccinated employees/number of eligible employees) and compared the rate from the period before the mandatory vaccine policy with the rate from the current influenza season.

The number and proportion of exemptions was recorded, as well as the rates of employment termination following vaccine refusal. Health care-associated influenza rates were also compared to pre- and post-mandatory vaccine implementation.

With the implementation of the mandatory influenza vaccine policy, the proportion of vaccinated eligible CHOP employees increased from 91% in 2008 to 99.3% in 2018 (p<0.05) and the proportion of requested exemptions dropped from 2.5% in 2008 to 0.3% in 2018 (p<0.05). The rate of health care-associated influenza illness cases per season decreased from a median of 16.8 cases pre-policy rollout to 5.2 cases post-policy rollout (p<0.05).

Fifteen percent (2/13) of exemptions were granted for possible influenza vaccine allergy; 66% (2/3) for other vaccine/food allergy; and 4/20 (20%) for egg allergy. Religious exemptions were granted to a total of 48% (12/25) of employees who requested them.

Exemptions for neurological conditions were also granted—89% (8/9) with Guillian-Barre syndrome and all (5/5) with other neurologic conditions. All of the health care workers who requested exemptions for immunocompromising conditions (6/6) were granted one, and 2 exemptions were granted to pregnant employees. Through 2018, 5 employees were terminated for refusing to be vaccinated.

“A mandatory influenza policy succeeded in increasing the proportion of immunized HCW and decreasing the number of requested exemptions at a large academic pediatric hospital,” the investigators concluded. “Our investigation illustrates the need for education on the importance of vaccinating immunocompromised individuals, including pregnant women, the ability to successfully immunize patients with egg allergies, in addition to the challenges of navigating religious exemptions.”

The study, “Implementation of a Mandatory Influenza Vaccine Policy: A 10-year Experience,” was presented in an oral session on April 25, 2019, at SHEA in Boston, Massachusetts.