Repeated immunization with the inactivated influenza vaccine, or IIV, appeared to increase long-term protection against some respiratory illness episodes in children with pre-existing medical conditions, according to findings recently published in Annals of Family Medicine.
Researchers analyzed electronic health records of 4,183 children with pre-existing medical conditions to determine whether prior immunization altered the effect of IIV on primary care-diagnosed respiratory illness episodes during influenza seasons from 2004 to 2015.
Adjusted analyses showed lower odds for respiratory illness in children immunized with prior IIV vs. those without prior IIV immunization (OR = 0.61; 95% CI, 0.47-0.78 for the current year immunized and one IIV in the previous 2 years; and OR = 0.85; 95% CI, 0.68-1.07 for the current year immunized and two or more IIVs in the previous 3 years, including the prior year).
“This study shows that protection against seasonal [respiratory illness] is not attenuated after repeated annual inactivated influenza vaccine immunization in children with preexisting medical conditions. Interestingly, our findings suggest that repeated inactivated influenza vaccine immunization may even increase protection,” the researchers wrote. – by Janel Miller
- de Hoog MLA, et al. Ann Fam Med. 2019;doi:10.1370/afm.2340.
Disclosures: The authors report no relevant financial disclosures.