tetano
Editor, Senior Moderator
Prev Med
. 2023 Jun 28;107599.
doi: 10.1016/j.ypmed.2023.107599. Online ahead of print. Association of influenza vaccination or influenza virus infection history with subsequent infection risk among children: The Japan Environment and Children's Study (JECS)
Hiroshi Yokomichi[SUP] 1 [/SUP], Mie Mochizuki[SUP] 2 [/SUP], Sayaka Horiuchi[SUP] 3 [/SUP], Megumi Kushima[SUP] 4 [/SUP], Ryoji Shinohara[SUP] 5 [/SUP], Reiji Kojima[SUP] 6 [/SUP], Tadao Ooka[SUP] 7 [/SUP], Yuka Akiyama[SUP] 8 [/SUP], Kunio Miyake[SUP] 9 [/SUP], Sanae Otawa[SUP] 10 [/SUP], Zentaro Yamagata[SUP] 11 [/SUP]; Japan Environment and Children's Study Group
Affiliations
We measured the association between history of influenza vaccination by age 2 years and influenza virus (IFV) infection at ages 3 and 4 years by relative risk reduction. We also examined the association between history of IFV infection by age 2 years and recurrent IFV infection at age 3 years. This study included 73,666 children from a large Japanese birth cohort. Among children vaccinated never, once or twice when aged under 2 years, 16.0%, 10.8% and 11.3%, respectively, had been infected with IFV by age 3 years, and 19.2%, 14.5% and 16.0%, respectively, by age 4 years. Compared with no history of influenza vaccination, vaccination at ages 1 and/or 2 years reduced the risk of IFV infection at age 3 by 30%-32% and at age 4 by 17%-24%. The relative risk of recurrent IFV infection at ages 3 and 4 years increased in proportion to the number of prior infections by age 2. One-season-prior influenza vaccination history reduced the IFV infection risk at age 3 years by 25%-42%. Influenza vaccination most effectively protected children at age 3 who lacked older sibling(s) and did not attend nursery school. One-season-prior IFV infection increased the relative risk of recurrent infection at age 3 years (1.72-3.33). In conclusion, influenza vaccination-induced protection may partly extend to the next season. Owing to the relative risk reduction by influenza vaccination and the increased relative risk of IFV infection from prior-season infection, annual influenza vaccination is recommended.
Keywords: Children; Cohort study; Influenza vaccine; Influenza virus infection; Japanese; Nursery school; One-season-prior vaccination; Risk reduction; Toddlers; Vaccine effectiveness.
. 2023 Jun 28;107599.
doi: 10.1016/j.ypmed.2023.107599. Online ahead of print. Association of influenza vaccination or influenza virus infection history with subsequent infection risk among children: The Japan Environment and Children's Study (JECS)
Hiroshi Yokomichi[SUP] 1 [/SUP], Mie Mochizuki[SUP] 2 [/SUP], Sayaka Horiuchi[SUP] 3 [/SUP], Megumi Kushima[SUP] 4 [/SUP], Ryoji Shinohara[SUP] 5 [/SUP], Reiji Kojima[SUP] 6 [/SUP], Tadao Ooka[SUP] 7 [/SUP], Yuka Akiyama[SUP] 8 [/SUP], Kunio Miyake[SUP] 9 [/SUP], Sanae Otawa[SUP] 10 [/SUP], Zentaro Yamagata[SUP] 11 [/SUP]; Japan Environment and Children's Study Group
Affiliations
- PMID: 37391036
- DOI: 10.1016/j.ypmed.2023.107599
We measured the association between history of influenza vaccination by age 2 years and influenza virus (IFV) infection at ages 3 and 4 years by relative risk reduction. We also examined the association between history of IFV infection by age 2 years and recurrent IFV infection at age 3 years. This study included 73,666 children from a large Japanese birth cohort. Among children vaccinated never, once or twice when aged under 2 years, 16.0%, 10.8% and 11.3%, respectively, had been infected with IFV by age 3 years, and 19.2%, 14.5% and 16.0%, respectively, by age 4 years. Compared with no history of influenza vaccination, vaccination at ages 1 and/or 2 years reduced the risk of IFV infection at age 3 by 30%-32% and at age 4 by 17%-24%. The relative risk of recurrent IFV infection at ages 3 and 4 years increased in proportion to the number of prior infections by age 2. One-season-prior influenza vaccination history reduced the IFV infection risk at age 3 years by 25%-42%. Influenza vaccination most effectively protected children at age 3 who lacked older sibling(s) and did not attend nursery school. One-season-prior IFV infection increased the relative risk of recurrent infection at age 3 years (1.72-3.33). In conclusion, influenza vaccination-induced protection may partly extend to the next season. Owing to the relative risk reduction by influenza vaccination and the increased relative risk of IFV infection from prior-season infection, annual influenza vaccination is recommended.
Keywords: Children; Cohort study; Influenza vaccine; Influenza virus infection; Japanese; Nursery school; One-season-prior vaccination; Risk reduction; Toddlers; Vaccine effectiveness.