Determinants of measles seroprevalence among pregnant women in Paris, France.

Non-immune pregnant women are at risk of severe measles. As the measles vaccination is contraindicated during pregnancy, women should be vaccinated before conception or during the postpartum period. Nevertheless, measles serology is not recommended during pregnancy in France, and there are no data available concerning measles susceptibility and its associated risk factors among pregnant women. The socio-demographic determinants of measles seronegativity have been identified in a prospective cohort of 826 pregnant women in Paris, France. Measles seronegativity was 10.41% (95% CI 8.32-12.50). Women from higher socio-economic groups, born in France after 1980, were more frequently seronegative.

[Long term persistence of yellow fever neutralising antibodies in elderly persons]. / Persistance à long terme des anticorps neutralisants de la fièvre jaune chez les personnes âgées de 60 ans et plus.

The activity of the yellow fever virus is reemerging in areas without recent transmission history, such as northern Argentina and Paraguay, and persists in an epidemic mode in other countries in Africa and Latin America. Thus more and more travelers are at risk of being exposed to this disease. The population is becoming older, sometimes suffering from multiple pathologies. Moreover, the risk of serious adverse events associated with live-attenuated YF17D vaccine, such as multiple organ failure (YEL-AVD), reaches 1/50,000 vaccines in people over 65 versus 1/200,000 in the general population. We analyzed, in a retrospective study, the results of neutralizing antibody titers against yellow fever in people aged 60 and older, who had been previously vaccinated against yellow fever and had visited the International Vaccination Centre of the Institut Pasteur between January 2005 and February 2009. In this population of 84 persons (median age 69 years), the date of the last vaccination was always more than 10 years: it was precisely known in 68 subjects and alleged in 16 subjects. The median time since the previous vaccination was 14 years, with a maximum of 60 years. The indications of serology were: immunosuppressive therapy (19% of cases), cancer (32%), hemopathy (10.7%), HIV infection (3.6%), chronic hepatitis/chronic renal failure/dialysis (2.4%), autoimmune diseases (2.4%), and in 29.8% of cases, age alone was the indication of serology. The antibody titer was at a protective level in 95.2% of cases. The four individuals with negative serology had no formal documented proof of a previous vaccination against yellow fever. This serological study was able to show a persistent protective antibody titer, after a previous vaccination, even going back 60 years, allowing patients to travel in a yellow-fever endemic area despite a contraindication, and without requiring any vaccine booster.