Comparison of Serology and Reactogenicity between Influenza Subunit Vaccines and Whole Virus or Split Vaccines

Abstract

Currently three different inactivated influenza vaccine types are available: whole virus (WV), split (SPL) and subunit (SU) vaccines. Physicians and patients at risk for influenza complications may wonder whether there are important differences between the vaccine types with respect to antibody induction (serology) and adverse effects (reactogenicity). A literature review (1975 to 1995) was performed to evaluate the serology and reactogenicity of SU vaccines in comparison with either split or whole virus vaccines. 22 publications with randomised allocation were identified describing a total of 5416 serological observations, 2858 observations of local reactions, and 2990 observations of systemic reactions. Subjects included those from all age groups from children to the elderly. Absolute protection and reaction rate differences (RD) were calculated for the comparisons SU vs SPL or SU vs WV vaccine. These were subjected to a method of meta-analysis, resulting in pooled rate differences and their 95% confidence intervals. With the exception of the comparison SU vs WV vaccine in subjects born after 1957 and unexposed to the reappearing H1N1 subtype after 1977, no evidence was found to suggest relevant differences in seroresponse among the three currently available inactivated influenza vaccine types. Although insufficient data were available in the meta-analysis for vaccines in children for whom specific recommendations concerning these vaccines exist, adverse events after administration of any of the three vaccine types were generally mild and transitory; however, SU vaccines were associated with a lower frequency of local and systemic reactions.

Whole-Virion Influenza Vaccine Recalls an Early Burst of High-Affinity Memory B Cell Response through TLR Signaling

“…Whereas whole-virion vaccines are more immunogenic than other formulations (e.g., split and subunit vaccines) in humans and mice (7,(75)(76)(77)(78), they have been replaced by splitvirion types because of the high incidence of adverse effects such as febrile illness and local reactions at the injection site (79)(80)(81)(82). It is generally accepted that inflammatory cytokines produced from innate immune cells (i.e., DCs) are the primary cause of adverse effects in subjects vaccinated with whole-virion vaccines (75,83).…”

Improvement of H5N1 influenza vaccine viruses: Influence of internal gene segments of avian and human origin on production and hemagglutinin content

“…In addition, this procedure allows the removal of virulence determinants from viral proteins such as an oligobasic cleavage site within the HA protein. Many commercial manufacturers produce well tolerated seasonal "split vaccines" in which the bulk of vaccine virus is chemically inactivated and extracted with detergents and organic solvent to separate the immunogenic surface glycoproteins from reactogenic compounds [12] and [13]. The currently available H5N1 vaccines were shown to be safe and immunogenic when formulated as split-, adjuvanted whole virion-or subvirion vaccine [14], [15] and [16].…”

Influenza

“…De modo geral, as vacinas do tipo split e as vacinas subunitárias induzem resposta sorológica semelhante 6 ,…”