increasing but disparate coverage

Lhe scientific interest group (GIS) Epi-Phare presented the results of a French study [1, 2] on vaccination coverage against whooping cough for pregnant women, in the epidemic context of 2024 in France.

The objective of this work was to estimate the pertussis vaccination rate among pregnant women, as well as to study their characteristics and the factors influencing vaccination. It was not intended to provide data in terms of effectiveness.

Since 2022, in order to reduce the risk of severe forms of whooping cough in newborns and infants, vaccination is recommended from the second trimester of pregnancy (cf. our article of April 14, 2022), favoring the period between 20 and 36 weeks of amenorrhea (SA) [3]. This measure aims to protect the child from birth thanks to the transplacental transfer of maternal antibodies. This vaccination is recommended with each pregnancy.

Analysis methodology

This cross-sectional survey was carried out on the date of 1^is October 2024 on all women having declared a pregnancy whose presumed start date was between 1^is August 2023 and March 31, 2024, i.e. on 386,712 women.

In this population, a search for vaccination by REPEVAX or BOOSTRIXTETRA vaccines was carried out using Health Insurance reimbursement data.

Secondly, the analysis focused only on the population which, at the end of monitoring date set on 1^is October 2024, had reached at least 34 weeks of pregnancy (36 weeks of amenorrhea, in accordance with the recommendations of the High Authority of Health [HAS]) in order to allow time to be vaccinated, i.e. 304,534 women (cf. Figure).

Figure – Timeline representing the inclusion period, end of follow-up and exposure period

(cf. page 12 of the Epi-Phare report [2])

The authors also collected various characteristics as well as certain socio-demographic indicators.

A membership that increases every year

At the end of this analysis, the pertussis vaccination rate was:

• at 63.2% in the overall population having declared a pregnancy over the period studied, i.e. 244 422 women out of 386 712. More than 90 % had been vaccinated between the 18th^e and the 34^e week of pregnancy (from 20 to 36 weeks) in accordance with the recommendations;
• to 65.4% in the population of women who have reached at least 34 weeks of pregnancy at the end of follow-up.

For the authors, “These results show that vaccinating women during pregnancy against whooping cough (…) was widely followed during the 2023/2024 epidemic, despite its non-obligatory nature ».

They note a upward trend in vaccination rates since 2021 (data from the Epi-Mères pregnancy-child register):

• 65% in 2023/2024;
• 41% in 2023;
• 12% in 2022 (year of the HAS recommendation);
• 2% in 2021 (before the HAS recommendation).

But disparities which require targeted actions

Although the coverage of whooping cough vaccination is generally satisfactory, disparities are reported:

• regional marked by very high rates in the north and west, but low in the overseas departments and in regions of the south of France (cf. Boxed)
• socio-economic differences between vaccinated and unvaccinated women:
  • 16.7% of vaccinated women benefited from complementary solidarity health insurance against 32,1 %,
  • 3.9% of vaccinated women resorted to consultations with PMI services compared to 4.4%,
  • 22.1% of vaccinated women came from more advantaged municipalities compared to 16.6%,
  • 26.2% of women vaccinated lived in municipalities offering better potential localized accessibility to general practitioners, compared to 22.5%;
• age-related: women aged 25-35 were slightly more vaccinated than those in other age groups with respective rates of 64.7% versus 60.4%.

For the authors, “actions aimed at both reducing disparities at the regional level and improving the level of vaccination coverage in certain departments are still necessary ».