tetano
Editor, Senior Moderator
Influenza Other Respir Viruses
. 2023 Oct;17(10):e13213.
doi: 10.1111/irv.13213. No association between inactivated influenza vaccination and influenza viral load at diagnosis among young Japanese children: An observational study of the 2013/2014 through 2017/2018 influenza seasons
Emiko Mukai[SUP] 1 [/SUP], Wakaba Fukushima[SUP] 2 3 [/SUP], Saeko Morikawa[SUP] 4 [/SUP], Keiko Nakata[SUP] 4 [/SUP], Satoshi Hiroi[SUP] 4 [/SUP], Masashi Fujioka[SUP] 5 [/SUP], Tohru Matsushita[SUP] 6 [/SUP], Megumi Kubota[SUP] 7 [/SUP], Yoshina Yagi[SUP] 8 [/SUP], Tetsuhisa Takechi[SUP] 9 [/SUP], Yoshio Takasaki[SUP] 10 [/SUP], Shizuo Shindo[SUP] 11 [/SUP], Yuji Yamashita[SUP] 12 [/SUP], Takato Yokoyama[SUP] 13 [/SUP], Yumi Kiyomatsu[SUP] 14 [/SUP], Kazuhiro Matsumoto[SUP] 1 [/SUP], Akiko Maeda[SUP] 2 [/SUP], Kyoko Kondo[SUP] 15 [/SUP], Kazuya Ito[SUP] 16 [/SUP], Tetsuo Kase[SUP] 2 3 [/SUP], Satoko Ohfuji[SUP] 2 3 [/SUP], Yoshio Hirota[SUP] 17 [/SUP]
Affiliations
Background: The association between inactivated influenza vaccination and viral load in young children remains unclear.
Methods: During the 2013/2014 to 2017/2018 influenza seasons in Japan, children under 6 years of age with pre-defined influenza-like illness and influenza-positive status by real-time RT-PCR were recruited at pediatric clinics for this observational study. Influenza viral load was measured for the most predominant subtype/lineage in each season. Using median dichotomized viral load as an outcome, a multilevel logistic regression model was applied to estimate the multivariable adjusted odds ratio (MOR) and 95% confidence interval (CI) for higher viral load.
Results: A total of 1,185 influenza-positive children were analyzed. The median log[SUB]10[/SUB] viral load copy number (copies per milliliter) was 5.5 (interquartile range, 4.6 to 6.1) and did not differ by vaccination status: 5.5 for unvaccinated, 5.7 for one dose, and 5.5 for two doses (p = 0.67). The MOR of vaccinated (one or two doses) versus unvaccinated children was 1.19 (95% CI: 0.86-1.64). Other factors showing significant associations with higher viral load were positive results for A(H1N1)pdm09 and A(H3N2) in comparison with B/Yamagata. The respective MORs were 3.25 (95% CI: 2.28-4.64) and 1.81 (95% CI: 1.32-2.49). Significantly elevated MORs against higher viral load were also observed for higher body temperature at influenza diagnosis and shorter duration from fever onset to specimen collection.
Conclusion: No association was observed between inactivated-influenza vaccination and viral load at influenza-positive diagnosis. Influenza subtype/lineage, body temperature, and time elapsed since fever onset were significantly associated with viral load.
Keywords: fever; flu vaccine; influenza viral load; young children.
. 2023 Oct;17(10):e13213.
doi: 10.1111/irv.13213. No association between inactivated influenza vaccination and influenza viral load at diagnosis among young Japanese children: An observational study of the 2013/2014 through 2017/2018 influenza seasons
Emiko Mukai[SUP] 1 [/SUP], Wakaba Fukushima[SUP] 2 3 [/SUP], Saeko Morikawa[SUP] 4 [/SUP], Keiko Nakata[SUP] 4 [/SUP], Satoshi Hiroi[SUP] 4 [/SUP], Masashi Fujioka[SUP] 5 [/SUP], Tohru Matsushita[SUP] 6 [/SUP], Megumi Kubota[SUP] 7 [/SUP], Yoshina Yagi[SUP] 8 [/SUP], Tetsuhisa Takechi[SUP] 9 [/SUP], Yoshio Takasaki[SUP] 10 [/SUP], Shizuo Shindo[SUP] 11 [/SUP], Yuji Yamashita[SUP] 12 [/SUP], Takato Yokoyama[SUP] 13 [/SUP], Yumi Kiyomatsu[SUP] 14 [/SUP], Kazuhiro Matsumoto[SUP] 1 [/SUP], Akiko Maeda[SUP] 2 [/SUP], Kyoko Kondo[SUP] 15 [/SUP], Kazuya Ito[SUP] 16 [/SUP], Tetsuo Kase[SUP] 2 3 [/SUP], Satoko Ohfuji[SUP] 2 3 [/SUP], Yoshio Hirota[SUP] 17 [/SUP]
Affiliations
- PMID: 37885369
- DOI: 10.1111/irv.13213
Background: The association between inactivated influenza vaccination and viral load in young children remains unclear.
Methods: During the 2013/2014 to 2017/2018 influenza seasons in Japan, children under 6 years of age with pre-defined influenza-like illness and influenza-positive status by real-time RT-PCR were recruited at pediatric clinics for this observational study. Influenza viral load was measured for the most predominant subtype/lineage in each season. Using median dichotomized viral load as an outcome, a multilevel logistic regression model was applied to estimate the multivariable adjusted odds ratio (MOR) and 95% confidence interval (CI) for higher viral load.
Results: A total of 1,185 influenza-positive children were analyzed. The median log[SUB]10[/SUB] viral load copy number (copies per milliliter) was 5.5 (interquartile range, 4.6 to 6.1) and did not differ by vaccination status: 5.5 for unvaccinated, 5.7 for one dose, and 5.5 for two doses (p = 0.67). The MOR of vaccinated (one or two doses) versus unvaccinated children was 1.19 (95% CI: 0.86-1.64). Other factors showing significant associations with higher viral load were positive results for A(H1N1)pdm09 and A(H3N2) in comparison with B/Yamagata. The respective MORs were 3.25 (95% CI: 2.28-4.64) and 1.81 (95% CI: 1.32-2.49). Significantly elevated MORs against higher viral load were also observed for higher body temperature at influenza diagnosis and shorter duration from fever onset to specimen collection.
Conclusion: No association was observed between inactivated-influenza vaccination and viral load at influenza-positive diagnosis. Influenza subtype/lineage, body temperature, and time elapsed since fever onset were significantly associated with viral load.
Keywords: fever; flu vaccine; influenza viral load; young children.