The trends of acute hepatitis A and hepatitis E during the COVID-19 pandemic in Japan

ABSTRACT

Introduction: The prevalence of various infectious diseases has been changing since the COVID-19 pandemic in Japan. Hepatitis A (HA) is transmitted from food and drink contaminated with the hepatitis A virus, while hepatitis E (HE) is a known zoonotic disease. The trends of HA and HE infection during the COVID-19 pandemic are unknown in Japan. Objective(s) In this study, we investigated the incidence of HA and HE before and after the COVID-19 epidemic, and compared the differences in trends between our hospital and Japanese statistics. Method(s) We investigated the number of IgA-HEV and IgM-HAV antibodies tested and positive at our hospital between January 2015 and December 2021. We verified the patient background, blood test findings and outcome of each antibody-positive. Result(s) The number of HE diagnoses /tests (rate) was 2 /187 (1.1%) in 2015, 2 /155 (1.3%) in 2016, 7 /236 (3.0%) in 2017, 11 /234 (4.7%) in 2018 and 15/ 307 (4.9%) in 2019, which was an increasing trend, but the number of tests remained the same but the number of diagnoses decreased 6 /314 (1.9%) in 2020, 2 /296 (1.0%) in 2021. According to Japanese statistics, the number of HE diagnoses showed a gradual increase from 213 in 2015 to 490 in 2019, but a slight decrease was reported in 441 in 2020 and 447 cases in 2021, respectively. On the other hand, there was no marked change in the number of HA diagnoses/tests between 2015 and 2019. 7 cases of HIV co-infection and an epidemic among Men who have Sex with Men (MSM) were observed in 2018. The number of cases decreased markedly to 0 /362 (0%) in 2020 and 0 /339 (0%) in 2021. In Japan, the number of HA diagnoses was in the 200 s from 2015 to 2017, while 925 cases were diagnosed in 2018 and 425 cases in 2019, indicating an epidemic, but the number of HA diagnoses has decreased significantly to 118 in 2020 and 69 in 2021. Conclusion(s) The number of cases of HE, a zoonosis, was reported to have decreased slightly nationwide, even with the coronary disaster, but the number of cases decreased markedly at our facility in Tokyo, suggesting the influence of changes in the lifestyle and activity patterns of the patient population. On the other hand, the number of cases of HA, which had been prevalent in recent years as a result of sexual contact among MSM, has decreased, probably due to a decrease in the influx of cases from overseas as a result of travel restrictions.