Immunogenicity of a trivalent influenza vaccine and persistence of induced immunity in adults aged ≥60 years in Taizhou City, Zhejiang Province, China, during the 2018–2019 season

Abstract

Yearly administration of influenza vaccine with recommendations can help control seasonal influenza epidemics in adults aged ≥60 years. Here, we describe the results of a prospective study observing the immunogenicity and persistence of induced immunity of a trivalent inactivated split-virion influenza vaccine (TIV) in adults aged ≥60 years during the 2018–2019 season in Taizhou City, Zhejiang Province in China. A total of 422 participants completed the study period. Vaccinated participants (284) received a single dose of TIV, but unvaccinated participants (138) didn’t receive any vaccine. Study participants vaccinated with TIV had significantly higher GMTs of Hemagglutination Inhibition (HI) antibodies against AH1N1, AH2N3, and B/Victoria strains (all p < .0001) at day 30 post-vaccination compared with unvaccinated participants, but the antibody response to the B/Victoria strain was the weakest. Rates of seroprotection and seroconversion were generally higher in the TIV-vaccinated group. At day 180 post-vaccination, the seroconversion rates (95%CI) in the vaccinated group were 99.6% (99.0%–100.3%), 97.9% (96.2%–99.6%), and 68.3% (62.9%–73.8%) for antibodies against three influenza strains, respectively; these rates were significantly different compared with unvaccinated group only for strains AH3N2 and B/Victoria ( p = .002 and p < .0001, respectively). These results confirm that in adults aged ≥60 years, a single dose of TIV can induce a protective immune response against influenza, but the protective HI antibody levels induced against strain B/Victoria do not persist through 6 months.

Safety and immunogenicity of locally produced trivalent inactivated influenza vaccine (Tri Fluvac) in healthy Thai adults aged 18–64 years in Nakhon Phanom: A Phase III double blinded, three-arm, randomized, controlled trial

“…GMTs were highest against the H3 strain and about 2.5 times lower against the B strain, but this was similar for the comparator (3 times lower). Although some studies showed comparable high antibody response to all three vaccine strains [13] , [14] , previous investigators reported lower response to influenza B [15] , [16] , [17] . This finding may depend on the properties of influenza B strain used in different studies.…”

Sustained Vaccine Exposure Elicits More Rapid, Consistent, and Broad Humoral Immune Responses to Multivalent Influenza Vaccines

“…In contrast, standard liquid bolus vaccine groups typically exhibited at least 20% non-responders to the homologous influenza strains incorporated in the vaccine. Effective seroconversion against administered strains varies widely in a clinical setting, with seroconversion rates among vaccinated adults often varying from 30-70% one month after vaccination [65][66][67] . The ability of PNP hydrogel based multivalent vaccines to induce consistently complete seroconversion is a marked improvement over current commercial vaccine technologies.…”

Inactivated Poliovirus Vaccine Booster Reduces the Likelihood of COVID-19 Outcomes in Individuals Primed with Oral Poliovirus Vaccination

“…While the initial hypothesis projected that receipt of vaccinations, including influenza, COVID-19, and Tdap, as well as durations between vaccinations and SARS-CoV-2 exposures may impact the odds of testing positive, experiencing symptoms, or the duration of COVID-19 symptoms, the multivariate regression models did not reveal such influences. There were no significant differences between participants who had recently received influenza, COVID-19, or Tdap vaccinations and those who had not, nor between those who had received vaccinations greater or less than 6 months prior to SARS-CoV-2 exposures, when antibodies are known to wane [ 66 , 70 , 71 , 74 , 76 , 77 ]. Future trials should investigate whether IPV inoculation may complement other vaccines, such as influenza and COVID-19, and boost antibodies for a longer duration.…”

“…In any event, researchers recommend additional COVID-19 vaccinations, to serve as "booster shots," to maintain higher antibody levels [67,68]. In terms of immunity, it takes about 2 weeks to mount antibodies from influenza vaccines, with immunity peaking 2 to 4 weeks later and waning between 3 and 6 months after inoculation [73][74][75][76][77]. While it is not known how long poliovirus antibodies last, studies have shown that individuals can still be completely resistant to wild poliovirus 10 or even 18 years after receiving OPV, and some assert that protective effects could potentially last a lifetime [78][79][80].…”