The influence of vaccination on the clinical features of hemorrhagic fever with renal syndrome in the last 5 years

Lee, Namseok; Kim, Hyo Youl; Chae, Myeong Hun; Kim, Eunmi; Park, So Yeon; Han, Sang Hoon; Kwon, Ohgun; Uh, Young

Abstract

BACKGROUND/AIMS: Hemorrhagic fever with renal syndrome (HFRS) caused by Hantaan virus is an endemic febrile disease in Korea. Although inactivated Hantaan virus vaccine has been introduced, the effect of vaccination is not clear. We evaluated the effect of vaccination on the incidence rate and clinical features of HFRS based on our clinical experience.
METHODS
Group I consisted of the patients with confirmed HFRS from a total of 131 patients who were seropositive for Hantaan virus at one tertiary teaching hospital from January 2002 to December 2006. Group II contained 100 patients treated as HFRS at the same hospital from January 1986 to December 1990, before the introduction of the vaccine. Then, we compared the clinical features of the two groups. We confirmed whether the patients had been vaccinated by reviewing their medical records and from telephone interviews.
RESULTS
Only 16 (12.2%) of the 131 patients who were seropositive for Hantaan virus were confirmed to have overt HFRS during the most recent 5 years. The incidence of overt HFRS was significantly lower in vaccinees (5%, 3 of 56) than in non-vaccinees (20%, 10 of 50) (p=0.025). The prevalence of renal failure (62.5 vs. 95%, p<0.001) and oliguria (6.25 vs. 46%, p=0.002) was significantly lower in group I than in group II. Three patients were treated with dialysis and none died in group I, versus 17 and 8, respectively, in group II.
CONCLUSIONS
It appears that Hantaan virus vaccine has helped to reduce the amount of serious illness and the occurrence of HFRS.