Prospective hospital-based cohort studies of Respiratory Syncytial Virus (RSV) infections in infants under one year during and after the SARS-CoV-2 pandemic in Japan

Koo Nagasawa; Mihoko Ohata; Ataru Igarashi; Takeshi Arashiro; Tomoko Ogawa; Misako Ohkusu; Noriko Takeuchi; Kenichi Shizuno; Erika Kurihara; Misato Yoshida; Takahiro Kodama; Katsuaki Abe; Tadashi Hoshino; Junko Arii; Kenichi Takeshita; Haruka Hishiki; Setsuo Ota; Yoshiko Takahashi; Yuko Omata; Tomoko Nakazawa; Tomohiro Someya; Naruhiko Ishiwada

doi:10.1016/j.ijid.2024.107252

Prospective hospital-based cohort studies of Respiratory Syncytial Virus (RSV) infections in infants under one year during and after the SARS-CoV-2 pandemic in Japan

Int J Infect Dis. 2024 Sep 28:149:107252. doi: 10.1016/j.ijid.2024.107252. Online ahead of print.

Authors

Koo Nagasawa¹, Mihoko Ohata², Ataru Igarashi³, Takeshi Arashiro⁴, Tomoko Ogawa⁵, Misako Ohkusu², Noriko Takeuchi², Kenichi Shizuno⁶, Erika Kurihara⁷, Misato Yoshida⁸, Takahiro Kodama⁸, Katsuaki Abe⁹, Tadashi Hoshino¹⁰, Junko Arii¹¹, Kenichi Takeshita¹¹, Haruka Hishiki¹², Setsuo Ota¹², Yoshiko Takahashi¹³, Yuko Omata¹³, Tomoko Nakazawa¹³, Tomohiro Someya¹⁴, Naruhiko Ishiwada¹⁵

Affiliations

¹ Department of Pediatrics, Chiba University Hospital, Chiba-city, Chiba, Japan.
² Department of Infectious Diseases, Medical Mycology Research Center, Chiba University, Chiba-city, Chiba, Japan.
³ Department of Public Health, Yokohama City University School of Medicine, Yokohama-city, Kanagawa, Japan.
⁴ Sanofi Vaccines Medical, Shinjuku-ku, Tokyo, Japan.
⁵ Department of Pediatrics, Chiba University Hospital, Chiba-city, Chiba, Japan; Department of Infectious Diseases, Medical Mycology Research Center, Chiba University, Chiba-city, Chiba, Japan.
⁶ Department of Clinical Laboratory, Chiba Kaihin Municipal Hospital, Chiba-city, Chiba, Japan.
⁷ Department of Pediatrics, Chiba University Hospital, Chiba-city, Chiba, Japan; Department of Pediatrics, Chiba Kaihin Municipal Hospital, Chiba-city, Chiba, Japan.
⁸ Department of Pediatrics, Chiba Kaihin Municipal Hospital, Chiba-city, Chiba, Japan.
⁹ Department of Pediatrics, Kamagaya General Hospital, Kamagaya-city, Chiba, Japan.
¹⁰ Department of Infectious Diseases, Chiba Children's Hospital, Chiba-city, Chiba, Japan.
¹¹ Department of Pediatrics, Chiba Rosai Hospital, Ichihara-city, Chiba, Japan.
¹² Department of Pediatrics, Teikyo University Chiba Medical Center, Ichihara-city, Chiba, Japan.
¹³ Department of Pediatrics, Seikei-kai Chiba Medical Center, Chiba-city, Chiba, Japan.
¹⁴ Department of Pediatrics, Goi Hospital, Ichihara-city, Chiba, Japan.
¹⁵ Department of Infectious Diseases, Medical Mycology Research Center, Chiba University, Chiba-city, Chiba, Japan. Electronic address: [email protected].

PMID: 39343126
DOI: 10.1016/j.ijid.2024.107252

Abstract

Objectives: In Japan, population-based epidemiological data on respiratory syncytial virus (RSV) infections are limited. To elucidate the epidemiology of RSV before the introduction of new prophylactic drugs, we conducted a population-based study during and after the SARS-CoV-2 pandemic.

Methods: This study was performed in four hospitals in Chiba City and three hospitals in Ichihara City. Clinical information and residual samples from RSV rapid antigen tests of infants under one year old were collected. Samples from patients with lower respiratory tract infections (LRTI) were analyzed using the FilmArray Respiratory 2.1 panels.

Results: A total of 1200 infants underwent the RSV rapid antigen test, with 497 diagnosed with LRTI. Although five samples could not be stored, 252 out of 492 (51.2%) were positive for RSV. Among the RSV PCR-positive infants, 63 (25.0%) had underlying diseases, compared to 100 out of 240 (41.7%) RSV PCR-negative infants (P < 0.05). In Chiba City, the annual incidence of hospitalization per 1000 children was 12.7 in 2021, 4.4 in 2022, and 9.2 in 2023.

Conclusions: During and after the SARS-CoV-2 pandemic, most hospitalized infants with RSV-LRTI did not have underlying diseases. Widespread use of prophylaxis in infants without underlying disease is desirable.

Keywords: Epidemiology; Hospitalization rate; Infants; Population; Respiratory syncytial virus.