RESUMEN
To evaluate the changes in respiratory syncytial virus (RSV) collected between 2019 and 2022, we analyzed RSV-A and RSV-B strains from various prefectures in Japan before and after the COVID-19 pandemic. RT-PCR-positive samples collected from children with rapid test positivity at outpatient clinics in 11 prefectures in Japan were sequenced for the ectodomain of the G gene to determine the genotype. Time-aware phylogeographic analyses were performed using the second hypervariable region (HVR) of the G gene from 2012 to 2022. Of 967 samples, 739 (76.4%) were found to be RSV-positive using RT-PCR. RSV peaked in September 2019 but was not detected in 2020, except in Okinawa. Nationwide epidemics occurred with peaks in July 2021 and 2022. The genotype remained the same, ON1 for RSV-A and BA9 for RSV-B during 2019-2022. Phylogeographic analysis of HVR revealed that at least seven clusters of RSV-A had circulated previously but decreased to two clusters after the pandemic, whereas RSV-B had a single monophyletic cluster over the 10 years. Both RSV-A and RSV-B were transferred from Okinawa into other prefectures after the pandemic. The RSV epidemic was suppressed due to pandemic restrictions; however, pre-pandemic genotypes spread nationwide after the pandemic.
Asunto(s)
COVID-19 , Infecciones por Virus Sincitial Respiratorio , Virus Sincitial Respiratorio Humano , Niño , Humanos , Lactante , Infecciones por Virus Sincitial Respiratorio/epidemiología , Pandemias , Epidemiología Molecular , Japón/epidemiología , COVID-19/epidemiología , Filogenia , Virus Sincitial Respiratorio Humano/genética , GenotipoRESUMEN
BACKGROUND: The objective of this study was to evaluate the effects of breastfeeding on the severity of respiratory syncytial virus infection in early infancy. METHODS: A rapid test for respiratory syncytial virus (RSV) was administered by 16 general pediatricians from May 2002 to April 2005 in infants undergoing medical checkups for the common cold, all of whom were 100 days old or younger and had birthweights of more than 2500 g without underlying disease. Infants were divided into three groups: the Full breastfeeding group, the Partial group, and the Token group. RSV-positive cases were followed up for 10 days after the initial diagnosis and the following three points were investigated: (i) the incidence of hospitalization; (ii) the duration of hospitalization; and (iii) the incidence of requiring oxygen therapy. RESULTS: RSV antigen was detected in 203 of the total of 892 cases, and these were diagnosed as cases of RSV infectious disease. Although there were no significant differences in the hospitalization rate among the three groups, there were significant differences in the duration of hospitalization and the rate of requiring oxygen therapy. Multivariate logistic regression revealed that the requirement of oxygen therapy was significantly lower in the Full breastfeeding group (P= 0.032; odds ratio, 0.256; 95% confidence interval, 0.074-0.892). CONCLUSIONS: Breastfeeding reduces the severity of respiratory syncytial virus infection in early infancy.