Hemagglutinin- and neuraminidase-targeting antibody responses after receipt of egg-based inactivated or recombinant influenza vaccines among adults aged 18-64 years.
Vasiliy P Mishin, Mira C Patel, Rongyuan Gao et al.
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In 30 seconds
This randomized trial compared hemagglutinin (HA)- and neuraminidase (NA)-targeting antibody responses after 2022–2023 recombinant influenza vaccine (RIV) or standard-dose inactivated influenza vaccine (SD-IIV) in adults aged 18–64 years. RIV recipients had two-fold higher anti-HA responses to cell-based type A and B/Yamagata viruses; the difference for B/Victoria was not statistically significant. SD-IIV did not produce a rise in NA-inhibiting antibodies to mammalian cell-grown viruses, although responses to egg-grown NA antigens increased. The findings highlight that measured antibody responses depend on the virus substrate used in testing.
Key findings
- Anti-HA responses to cell-based type A and B/Yamagata viruses were two-fold higher with RIV than SD-IIV.
- SD-IIV recipients showed no rise in NA-inhibiting antibodies to mammalian cell-grown viruses.
- After SD-IIV, ≥ 4-fold rises in ELLA GMTs occurred for egg-prepared N1 in 13% and N2 in 37% of recipients.
- Neutralizing antibodies waned faster than HI antibodies to most vaccine viruses.
Why it matters
The study shows that vaccine-associated antibody findings can differ according to whether test antigens are egg- or cell-grown, particularly for NA. This matters when interpreting immunogenicity studies and comparing vaccine responses: assays using egg-grown antigens may capture responses that are not evident against mammalian cell-grown viruses. HA and NA measurements therefore provide complementary information about humoral responses.
What to keep in mind
The antibody analyses were conducted in a subgroup of trial participants, and the reported outcomes are immunologic measures rather than clinical influenza outcomes.