Vaccine Efficacy and Immunogenicity in SARS-CoV-2 Dynamics

Understanding the interplay between vaccine efficacy—the ability to prevent infection and disease in controlled settings—and immunogenicity—the capacity to elicit immune responses—is vital to controlling SARS-CoV-2 transmission. Early clinical trials established high efficacy of mRNA and vector-based vaccines against ancestral strains, yet viral evolution and waning immunity have necessitated ongoing evaluation. Immunogenicity metrics, including neutralising antibody titres and T-cell responses, inform correlates of protection and guide booster schedules. Global surveillance has revealed variable effectiveness across demographic groups and distinct variants, emphasising the importance of optimised dosing intervals and heterologous boosting. Maintaining durable immunity and curbing breakthrough infections remain central to pandemic management and the design of next-generation vaccines with broad, variant-spanning coverage.

Research from Nature Portfolio

Real-world serological surveillance during an Omicron BA.2 wave in an infection-naive urban population demonstrated that three or four doses of mRNA or inactivated vaccines confer moderate protection against infection, but that vaccine effectiveness declines markedly within three months, highlighting the need for updated formulations and accelerated booster deployment. A randomised trial of a heterologous adenovirus-vectored booster following a three-dose inactivated vaccine regimen showed substantially higher receptor-binding domain IgG levels and neutralising titres against Omicron subvariants compared with a homologous boost, with durable responses at 90 days. In a large test-negative design, three doses of an mRNA vaccine maintained over 85 percent effectiveness against hospitalisation with Delta or Omicron for at least two months, whereas protection against mild infection waned more rapidly, emphasising the value of additional doses to prevent severe outcomes.

Vaccine Efficacy and Immunogenicity in SARS-CoV-2 Dynamics publication trend

The graph below shows the total number of articles in vaccine efficacy and immunogenicity in sars-cov-2 dynamics across all publications each year (not limited to Nature Index journals).

Technical terms

Vaccine efficacy: The percentage reduction of disease incidence in vaccinated individuals compared with unvaccinated controls under trial conditions.

Immunogenicity: The ability of a vaccine to induce an immune response, typically measured by antibody titres and T-cell activation assays.

Neutralising antibody: An antibody that inhibits viral entry into host cells by blocking key surface proteins.

Waning immunity: The gradual decline in immune protection over time following vaccination or natural infection.

Heterologous booster: A booster dose that uses a different vaccine platform or antigen formulation from the primary series.

Breakthrough infection: An infection occurring in a fully vaccinated individual, often due to immune evasion by viral variants.

References

1. Real-world COVID-19 vaccine effectiveness against the Omicron BA.2 variant in a SARS-CoV-2 infection-naive population. Nature Medicine (2023).
2. Safety and immunogenicity of Ad5-nCoV immunization after three-dose priming with inactivated SARS-CoV-2 vaccine in Chinese adults. Nature Communications (2023).
3. Effectiveness of COVID-19 vaccines against Omicron and Delta hospitalisation, a test negative case-control study. Nature Communications (2022).
4. Comparative effectiveness of BNT162b2 versus mRNA-1273 covid-19 vaccine boosting in England: matched cohort study in OpenSAFELY-TPP. The BMJ (2023).
5. COVID-19 vaccine waning and effectiveness and side-effects of boosters: a prospective community study from the ZOE COVID Study. The Lancet Infectious Diseases (2022).
6. Severe COVID-19 outcomes after full vaccination of primary schedule and initial boosters: pooled analysis of national prospective cohort studies of 30 million individuals in England, Northern Ireland, Scotland, and Wales. The Lancet (2022).