Influenza Vaccination for Immunocompromised Patients: Systematic Review and Meta-Analysis from a Public Health Policy Perspective

Abstract

BackgroundImmunocompromised patients are vulnerable to severe or complicated influenza infection. Vaccination is widely recommended for this group. This systematic review and meta-analysis assesses influenza vaccination for immunocompromised patients in terms of preventing influenza-like illness and laboratory confirmed influenza, serological response and adverse events.Methodology/Principal FindingsElectronic databases and grey literature were searched and records were screened against eligibility criteria. Data extraction and risk of bias assessments were performed in duplicate. Results were synthesised narratively and meta-analyses were conducted where feasible. Heterogeneity was assessed using I2 and publication bias was assessed using Begg's funnel plot and Egger's regression test. Many of the 209 eligible studies included an unclear or high risk of bias. Meta-analyses showed a significant effect of preventing influenza-like illness (odds ratio [OR] = 0.23; 95% confidence interval [CI] = 0.16–0.34; p<0.001) and laboratory confirmed influenza infection (OR = 0.15; 95% CI = 0.03–0.63; p = 0.01) through vaccinating immunocompromised patie nts compared to placebo or unvaccinated controls. We found no difference in the odds of influenza-like illness compared to vaccinated immunocompetent controls. The pooled odds of seroconversion were lower in vaccinated patients compared to immunocompetent controls for seasonal influenza A(H1N1), A(H3N2) and B. A similar trend was identified for seroprotection. Meta-analyses of seroconversion showed higher odds in vaccinated patients compared to placebo or unvaccinated controls, although this reached significance for influenza B only. Publication bias was not detected and narrative synthesis supported our findings. No consistent evidence of safety concerns was identified.Conclusions/SignificanceInfection prevention and control strategies should recommend vaccinating immunocompromised patients. Potential for bias and confounding and the presence of heterogeneity mean the evidence reviewed is generally weak, although the directions of effects are consistent. Areas for further research are identified.

Influenza vaccination for immunocompromised patients: summary of a systematic review and meta‐analysis

“…There was limited evidence of a transient increase in viraemia and a decrease in CD4% in HIV patients although this was not accompanied by a worsening of clinical symptoms. Further exposition of the evidence including statistical detail from our meta‐analyses of outcome measures stratified by aetiology of immunocompromise has been published elsewhere 7, 8…”

“…The methodology used in this study has been previously described, and an abbreviated protocol is also available from the National Institute for Health Research international prospective register of systematic reviews (PROSPERO) 7, 8, 9. We defined the study population according to policy documents published by the World Health Organization and United Kingdom Departments of Health for persons with primary or secondary immunodeficiency 2, 10.…”

“…Two manuscripts arising from this work have been published and report our findings through a public health policy interpretation and a sub‐analysis by aetiology of immunocompromise 7, 8…”

Vaccination Attitudes Among Patients with Cancer Receiving Chemotherapy.

“…Vaccine response rates are generally lower in patients with hematological malignancies compared to those with solid tumors.4 A recent meta-analysis showed lower rates of seroconversion for seasonal influenza A (H1N1), A (H3N2) and B but similar level of clinical protection against influenza with vaccination while toxicity was similar with immunocompetent controls. 19 In general, inactivated vaccines should be given at least 2 weeks before the initiation of chemotherapy to maximize the immune response. Although antibody responses are suboptimal, vaccination with inactivated vaccines is crucial given the similar level of clinical protection and favorable risk-benefit profile.…”

Safety and Immunogenicity of a Vero Cell Culture-Derived Whole-Virus H5N1 Influenza Vaccine in Chronically Ill and Immunocompromised Patients

“…Immune dysfunction associated with underlying medical conditions or immunosuppression might reduce vaccine responses, and there has been a perception that the vaccination of some risk populations may be associated with increased side effects (18,19). Particularly in a pandemic setting, where vaccines may be in short supply, it is crucial that the priority vaccination of specific groups is supported by data demonstrating that vaccination will be well tolerated and clinically beneficial (19).…”