Immunogenicity of influenza vaccine in elderly people: a systematic review and meta-analysis of randomized controlled trials, and its association with real-world effectiveness

Abstract

Background: Older people (≥60 years old) are particularly vulnerable to influenza virus infection, and vaccine is effective in reducing the disease burden in this population. However, it remains obscure whether their antibody response is lower than those of younger adults (18-60 years old). Thus, this meta-analysis was performed to compare the immunogenicity of influenza vaccines and understand their association with real-world vaccine effectiveness (VE) between these two age groups. Methods: A systematic literature search was conducted to identify relevant studies from Jan 01, 2008 to Nov 10, 2018. These are randomized controlled trials that included older adult samples, which assessed the immunogenicity of inactivated quadrivalent influenza vaccines produced in embryonated eggs. We excluded the studies focused only in children or adults. The outcomes were seroprotecton rate (SPR) and seroconversion rate (SCR). Results: Six studies were eventually included in the present meta-analysis (7,976 participants). For the SPR, the pooled risk ratio (RR) was 0.92 (95% CI: 0.90-0.94, I 2 = 66%, P < .0001) for A/H1N1 and 0.94 (95% CI: 0.90-0.98, I 2 = 91%, P = .002) for B/Victoria, and the antibody responses of A/H3N2 and B/Yamagata were similar in the two age groups. For the SCR, the pooled RR was 0.85 (95% CI: 0.76-0.94, I 2 = 93%, P = .003), 0.77 (95% CI: 0.66-0.91, I 2 = 94%, P = .002), and 0.83 (95% CI: 0.71-0.96, I 2 = 94%, P = .02) for A/ H1N1, B/Victoria and B/Yamagata, respectively, and the antibody responses of A/H3N2 were similar in the two groups. Some variations were found in the antibody responses across virus types and subtypes after influenza vaccination. Conclusion:The SPR and SCR of older adults were lower than those in younger adults for A/H1N1 and B/Victoria, while the two age groups had similar antibody responses for A/H3N2. The antibody responses to vaccines were not significantly associated with real-world VE, indicating that antibody response might not fully reflect the vaccine effectiveness of A/H3N2.

Should we vaccinate the better seroconverters or the most vulnerable? Game changing insights for COVID-19 vaccine prioritization policies

“…A systematic review and meta-analysis concluded that the seroprotection rate (SPR) and seroconversion rate (SCR) of older adults for A/H1N1 and B/Victoria were lower than those of younger adults, whereas the two age groups had similar antibody responses for A/H3N2 [ 24 ].…”

O Desamparo Jurídico No Regime De Teletrabalho Em Época De Pandemia

“…Os sinais e sintomas nos pacientes, no início de ambas as patologias, SARS e MERS, são febre, mialgia, fadiga, tosse e em grande parte dos pacientes, dispneia. A presença de diarreia, dor de cabeça, tosse com sangue e escarro, são menos comuns (HUANG et al, 2020;GUAN et al 2020;WANG et al, 2020) 2020).…”

“…Isso explica a grande ênfase das autoridades sanitárias para que as mãos sejam lavadas e/ou desinfetadas com álcool gel 70%, evitando que caso elas sejam levadas aos olhos, contaminem o paciente (HUANG et al 2020).…”

OVX836 Heptameric Nucleoprotein Vaccine Generates Lung Tissue-Resident Memory CD8+ T-Cells for Cross-Protection Against Influenza

“…The presence of antibodies directed against the HA glycoprotein on the virus surface which is subject to substantial immune selection pressure is considered the principal reference for protection against influenza viruses. However, vaccination strategies targeting influenza surface glycoproteins frequently have suboptimal effectiveness due to 1) virus mismatches ( 2 , 3 ) and 2) low humoral responses in fragile populations ( 4 ). Nonetheless, CD8+ cytotoxic T-cells also play a role in the mechanisms that protect against influenza ( 5 , 6 ).…”