Is it time to administer acellular pertussis vaccine to childbearing age/pregnant women in all areas using whole-cell pertussis vaccination schedule?

Background: Whole-cell pertussis (wP) vaccine administration is still advocated for children under 7 years of age in Iran. However, there is no recommendation for the administration of a dose of tetanus, diphtheria, and acellular pertussis (Tdap) vaccine to childbearing age/pregnant women in the Iranian vaccination program and it has increased the risk of infection through waning immunity during women's childbearing age life. The study aimed to assess the levels of anti-Bordetella pertussis antibodies in childbearing age women of different ages in Iran.

Methods: A cross-sectional study was conducted on a total number of 360 childbearing age women divided into six age groups, with 5-year intervals from 15 to 45 years old, in 2018-2019. Then, the levels of immunoglobulin A (IgA), immunoglobulin M (IgM), and immunoglobulin G (IgG) antibodies against B. pertussis were evaluated using enzyme-linked immunosorbent assay (ELISA). The IBM SPSS Statistics software (version 16.0) (SPSS Inc., Chicago, IL, USA) was used for data analysis.

Results: The mean age of the participants was 30.01 ± 8.35 years (range 14-45 years). All the cases were IgM negative, but two IgA-positive individuals (in the age groups of 14-19 and 30-34 years) were reported. Overall, 239 (66.4%) cases were IgG positive. The mean age of IgG-positive cases was 30.37 ± 8.37 years. The IgG-positive cases were mostly in the age groups of 30-34 and 35-39 years [43 (71.1%)]. The odds of IgG positivity were 1.97. The highest odds of IgG positivity were seen in 30-34 and 35-39 years groups (2.52) and the lowest odds were seen in the 20-24 and 25-29 years groups (1.60). Using the Jonckheere-Terpstra test, the increasing trend of IgG changes in different age groups was not statistically significant (Tπ=5.78, p = 0.09).

Conclusion: The infants of women of childbearing age might be prone to pertussis in countries using the wP vaccination schedule. It is suggested to administer a dose of Tdap to women before or during pregnancy to increase the immunity of their infants against this disease during early infancy.