(P54) ANALYSIS OF MPOX SYMPTOMS IN VACCINATED AND UNVACCINATED CASES IN FLORIDA FROM JANUARY 1, 2023, TO FEBRUARY 29, 2024

Background:
In August 2022, the JYNNEOS vaccine was authorized under an Emergency Use Authorization for individuals >18 years at high risk for infection by the mpox virus and those with known or suspected contact to someone with mpox. This study investigates the effect of receiving vaccine on the symptoms and severity of disease.

Methods:
Between January 1, 2023, and February 29, 2024, the Florida Department of Health was notified of 154 mpox cases with 45 positive for HIV including 14 patients living with AIDS. Twenty-six of all cases received one or more doses of vaccine ≥14 days before onset of symptoms including six cases with HIV and two with AIDS. Statistical significance between vaccinated and unvaccinated cases was calculated using odds ratio and 95% confidence interval for systemic symptoms (fever, myalgia, chills, sweats, fatigue, or headache) and symptoms with potential for severe sequela (rectal bleeding, rectal pain, difficulty defecating, or perianal lesions). Statistical significance for age was calculated using an unpaired t-test. Significance for severe mpox, defined as hospitalization, was calculated using an exact logistic regression.

Results:
Median time between last vaccine dose and symptom onset was 15 months (range 5-17 months). No statistical difference in median age, HIV status, or having one or more systemic symptoms was observed. Vaccinated individuals were more likely to have symptoms with potential for severe sequela (OR: 2.78, 95% CI: 1.10-7.03). All hospitalized cases (n=15) were unvaccinated including one death. While not statistically different, five unvaccinated AIDS cases were hospitalized including the fatal case, while two vaccinated cases were not.

Conclusion:
Vaccination may decrease the chance for hospitalization due to mpox but does not appear to remove the potential for symptoms that could result in severe sequela. Larger studies are needed particularly related to those living with HIV/AIDS who are at greater risk for severe or fatal mpox.