General information, not an individual diagnosis. Ask a healthcare professional if you are unsure about your situation.
A study can show that a vaccine produces an immune response without counting prevented infections. Immunogenicity and clinical effectiveness are therefore separate questions when you read a result.
Immunogenicity can be measured through antibody titres or seroconversion, meaning a change in the response detected after vaccination. These results describe laboratory measurements; they do not themselves count people who remained free of infection.
A clinical outcome can rely, for example, on the number of confirmed flu cases in the groups followed. Vaccination Info Service describes antibody measurement as an indirect measure of effectiveness: it does not automatically replace counting clinical events.
Early development phases investigate matters such as dose and immune response. Protective efficacy is mainly studied in phase III. Information should therefore specify which study objective was actually assessed.
The official flu document for 2026-2027 presents effectiveness and immunogenicity results separately. Reading an antibody titre in the latter section does not establish guaranteed protection for an individual.
To discuss a study, ask: ‘Was an immune response or actual disease measured?’ and ‘What conclusion about protection does the result support?’. This explanation sets no individual threshold and does not recommend an antibody test.
Sources
Vaccination
Flu and Covid-19: the 2026–2027 campaign
The national flu and Covid-19 vaccination campaign starts on 13 October 2026. In Doctolib, choose “Vaccination antigrippale (Grippe)” or “Vaccination COVID-19” for the vaccination you want to discuss.
Bring your carte Vitale and, for flu, your coverage voucher if you have one. The professional checks the recommendations and coverage conditions that apply to you.
The pharmacy checks whether vaccination and coverage apply based on the vaccine, your age and your circumstances.
Assurance Maladie — Campagne grippe 2026–2027 (9 octobre 2026) · Assurance Maladie — Campagne Covid-19 (30 septembre 2026) · Assurance Maladie — Vaccination par le pharmacien · Assurance Maladie — Prise en charge des vaccins · Ministère de la Santé — Calendrier vaccinal
Your health review
Review your health
Mon bilan prévention is an appointment to discuss your habits and choose your health priorities. Review the four age groups and practical information.