An inactivated Hantavirus vaccine was moderately effective against hemorrhagic fever with renal syndrome among South Korean military personnel, according to researchers.
The findings are important because they show a degree of protection against the illness (HFRS), which has a high mortality rate and no effective treatment, they wrote in The Journal of Infectious Diseases.
“This study demonstrated that [inactivated Hantavirus vaccine (IHV)] was moderately effective against HFRS in young adults,” researcher Kyungmin Huh, MD, MSc, a physician in the division of infectious diseases at Samsung Medical Center and Sungkyunkwan University School of Medicine in Seoul, and colleagues wrote. “To our knowledge, this is the first study that demonstrated a statistically significant effectiveness of IHV in a real-world setting.”
According to a vaccination policy, IHV was given to South Korean military personnel in divisions or battalions in which an HFRS case has occurred within the previous 3 years. The vaccination schedule includes two primary doses given 1 month apart, followed by a booster 12 months after the second dose.
To test the vaccine effectiveness (VE) of IHV, the researchers conducted a retrospective, matched case-control study. They identified 100 HFRS case patients diagnosed between January 2011 and February 2017. All patients were men, and 76% were enlisted soldiers. Each case was matched with one control who sought medical care for a non-HFRS notifiable disease.
Cases were defined as those with HFRS symptoms and confirmation of the disease using PCR, the presence of Hantavirus antibodies or rapid immunochromatography assay. The annual incidence rate was 30.16 cases per 100,000 population.
In all, 27% of case patients and 40% of control patients received at least one dose of IHV. The researchers estimated the overall adjusted VE at 58.9%. Adjusted VE was 78.7% in high-risk divisions and 83.8% among PCR-confirmed cases.
Adherence to the three-dose IHV schedule seemed low, Huh and colleagues said, and future research could focus on booster effects and other factors.
“No increase in [VE] after multiple doses was observed,” they wrote. “Further studies are warranted to evaluate the effect of booster doses and the safety of IHV.” – by Joe Green
The authors report no relevant financial disclosures.