Anti-measles antibodies, is there a way to detect their presence? In which cases is the adult vaccine needed?

Are there serological tests capable of establishing whether a person has antibodies and is therefore immune to measles (due to vaccination or previous illness)? If you are not vaccinated, is it useful to do so after contact with a sick person? If yes, within how long?

He replies Andrea Goriprofessor of Infectious Diseases at the University of Milan and head of the Infectious Diseases Unit of the ASST-Fatebenefratelli-Sacco, L. Sacco Hospital (GO TO THE FORUM)

First of all it is useful to remember that Measles is a viral disease that is transmitted through the respiratory system and is extremely contagious: in fact, it is estimated that more than 90% of non-immune people exposed to an infected individual become ill with measles. The disease, which in most cases has a favorable course, it can also have serious consequences, such as the development of potentially fatal pneumonia or encephalitisespecially if contracted in adulthood and in immunocompromised adults or children.

Epidemic outbreaks

Although vaccination has significantly reduced measles cases, epidemic outbreaks are far from rare, especially since vaccination rates are still far from the 95% safety threshold set by the World Health Organization. In Italy, in fact, in 2022, among the children for whom vaccination was indicated by the National Vaccine Prevention Plan, only 86% received both scheduled doseswith large differences between the various regions of Italy.

Over two hundred cases

The problem of measles is therefore more current than ever: in the first three months of 2024, 213 cases have already occurred in Italy (nine times out of ten in unvaccinated people), a clear increase compared to the same period of the previous year. In addition to vaccination, available in Italy since the end of the seventies, immunity to measles is also guaranteed by the natural disease, but for most people it is difficult to clearly reconstruct whether they have been affected by the pathology or not during childhood.

Antibody assay

So how can you find out if you are immune to measles? Today we can easily answer this question: it is, in fact, possible to measure the IgG antibodies for measles present in the blood through a simple blood sample, the prescription of which can be requested from your general practitioner. If these antibodies are absent or insufficient, you may decide to undergo vaccination regardless of the circumstances or to take this data into consideration if you come into contact with a person suffering from the disease.

When to get vaccinated

For non-immune people who have been exposed to a confirmed case of measles, there is, in fact, the indication to administer a dose of vaccine within 72 hours of contact. Vaccination is, therefore, the most effective weapon at our disposal and we must make full use of it, not only by vaccinating children extensively, but also by using it as adults in all necessary cases.