Modeling of antibody waning after heterologous boosting with Ad5-nCoV in individuals primed with two-dose CoronaVac previously.
Ruifan Shen, Lairun Jin, Xinglu Peng et al.
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In 30 seconds
This analysis integrated longitudinal serological data from three randomized trials in Jiangsu, China, to model antibody waning after aerosolized or intramuscular Ad5-nCoV boosting in people primed with two doses of CoronaVac, compared with a third CoronaVac dose. Linear mixed-effects models assessed exponential and power-law decay of neutralizing antibodies to SARS-CoV-2 variants. Power-law models fit better across all antibody types (all ΔAICc < 0). At day 90, estimated wild-type antibody half-lives were 195 d with aerosolized Ad5-nCoV, 226 d with intramuscular Ad5-nCoV, and 230 d with three-dose CoronaVac; estimates varied by variant.
Key findings
- Power-law decay models fit neutralizing-antibody data better than exponential models across all antibody types (all ΔAICc < 0).
- At day 90, wild-type neutralizing-antibody half-life was 195 d (95% CI: 185-210) after aerosolized Ad5-nCoV and 226 d (220-252) after intramuscular Ad5-nCoV, versus 230 d (95% CI: 222-257) after three-dose CoronaVac.
- For Omicron BA.1, estimated half-life was 314 d (248-453) after aerosolized Ad5-nCoV, 168 d (159-180) after intramuscular Ad5-nCoV, and 196 d (174-230) after three-dose CoronaVac.
Why it matters
Antibody waning estimates depend on the decay model used, and the better fit of power-law models may inform interpretation of post-booster serological follow-up. The variant-specific estimates also show that relative antibody persistence differed between aerosolized and intramuscular boosting, so a single half-life should not be assumed to apply across variants or regimens.
What to keep in mind
The findings are model-based estimates from serological data; the abstract does not report clinical protection outcomes.