Immunogenicity and safety of a quadrivalent inactivated influenza vaccine in pregnant women: a randomized, observer-blind trial

Abstract

Vaccination against influenza during pregnancy provides direct protection to pregnant women and indirect protection to their infants. Trivalent inactivated influenza vaccines (IIV3s) are safe and effective during pregnancy, but quadrivalent inactivated influenza vaccines (IIV4s) have not been evaluated in pregnant women and their infants. Here, we report the results of a randomized phase IV study to evaluate the immunogenicity and safety of IIV4 vs. IIV3 in pregnant women. Participants aged ≥18 years at weeks 20 to 32 of gestation were randomly assigned in a 2:1 ratio to receive a single dose of IIV4 (n = 230) or IIV3 (n = 116). Between baseline and 21 days after vaccination, hemagglutination inhibition (HAI) antibody titers increased in both groups by similar magnitudes for the two influenza A strains and single B strain common to IIV4 and IIV3. For the additional B strain in IIV4, HAI titers were higher in IIV4 recipients than IIV3 recipients (post-/prevaccination geometric mean titer ratio, 6.3 [95% CI: 5.1 − 7.7] vs. 3.4 [95% CI: 2.7 − 4.3]). At delivery, in both groups, HAI antibody titers for all strains were 1.5 − 1.9-fold higher in umbilical cord blood than in maternal blood, confirming active transplacental antibody transfer. Rates of solicited and unsolicited vaccine-related adverse events in mothers were similar between the two groups. Live births were reported for all participants and there were no vaccine-related adverse events in newborns. These results suggest IIV4 is as safe and immunogenic as IIV3 in pregnant women, and that maternal immunization with IIV4 should protect newborns against influenza via passively acquired antibodies.

Global Perspectives on Immunization During Pregnancy and Priorities for Future Research and Development: An International Consensus Statement

“…There is an extensive body of evidence in the literature from both HICs and LMICs that confirm the safety of maternal influenza vaccination (124)(125)(126)(127)(128)(129) [reviewed in (130)]. During the H1N1 influenza pandemic, data from Sweden and Argentina found that both AS03-adjuvanted and MF59-adjuvanted -H1N1 influenza vaccines were not associated with increased risk for low-birth weight or preterm birth or low Apgar score (131,132).…”

COVID-19 case management: The policy model in Morocco context

“…Furthermore, in vitro experiment, from multi European research collaboration, confirmed that quadrivalent inactivated influenza vaccine induces trained immunity responses against SARS-CoV-2 that enhance the COVID-19 protection[22]. Many previous studies demonstrated this vaccination benefice for pregnant women, and their newborns protected against influenza via passively acquired antibodies[23]. The quadrivalent vaccine immunogenicity and safety were confirmed for children aged 6-35 months and in older subjects aged 66-80 years[24].…”

“…If negative, another immediate RT-qPCR will be done from nasopharynx specimen If the viral load percentage is estimated clinically (low) between 32% and 05% just one RT-qPCR from the Nasopharynx should be done. 1 st Cq between [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] then control test Cq stays between [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33] (one week after) 1 st Cq between [16][17][18][19][20][21][22][23][24][25][26][27][28]…”

Influenza hospitalizations in children under 1 year old in Spain: the importance of maternal immunization

“…24 Recent studies with quadrivalent vaccines have shown vaccine effectiveness in pregnant women as well as the benefits for children. 25 This has allowed some vaccines to have, among their indications, the protection of pregnant women as well as children under 6 months of age by the transfer of antibodies from the mother to the child both during pregnancy and during lactation; i.e., passive protection of the infant from birth to 6 months of age after vaccination of the pregnant woman. 26 Other novel approaches, such as assessing both the safety of the seasonal influenza vaccine administered earlier in life, 3-4 months earlier than the current recommendation, especially in preterm infants that are at increased risk for influenza associated complications, and the impact of maternal antibodies on influenza vaccine responses are also being explored.…”