Pertussis vaccination in Chinese children with increasing reported pertussis cases

Abstract

In their Article, Juliette Paireau and colleagues1Paireau J Guillot S Aït El Belghiti F et al.Effect of change in vaccine schedule on pertussis epidemiology in France: a modelling and serological study.Lancet Infect Dis. 2021; (published online Oct 18.)https://doi.org/10.1016/S1473-3099(21)00267-XSummary Full Text Full Text PDF PubMed Scopus (4) Google Scholar mentioned that a change in vaccine schedule led to increased risk of developing pertussis and decreased anti-pertussis toxin IgG.1Paireau J Guillot S Aït El Belghiti F et al.Effect of change in vaccine schedule on pertussis epidemiology in France: a modelling and serological study.Lancet Infect Dis. 2021; (published online Oct 18.)https://doi.org/10.1016/S1473-3099(21)00267-XSummary Full Text Full Text PDF PubMed Scopus (4) Google Scholar Hence, it is of great value to modify the pertussis vaccination strategy in China. The number of cases of pertussis reported in China increased from 6658 in 2015 to 30 027 in 2019, and the actual number of cases is likely to be much higher (up to 16·22 times higher).2Huang H Zhu T Gao C et al.Epidemiological features of pertussis resurgence based on community populations with high vaccination coverage in China.Epidemiol Infect. 2015; 143: 1950-1956Crossref PubMed Scopus (23) Google Scholar Vaccination schedule is one of the most important factors related to the resurgence of pertussis when the diphtheria, tetanus, and whole-cell pertussis (DTwP) vaccine was replaced with the diphtheria, tetanus, and acellular pertussis (DTaP) vaccine after 2010. Anti-pertussis toxin IgG concentrations below the lower limit of detection (<5 IU/mL) were detected in 74·1% of pregnant women and 66·5% of newborn babies in China in 2016.3Meng QH Luo J Yang F et al.A general lack of IgG against pertussis toxin in Chinese pregnant women and newborns.Pediatr Infect Dis J. 2018; 37: 934-938Crossref PubMed Scopus (9) Google Scholar Low levels of anti-pertussis toxin IgG are strongly associated with immunisation strategies. Chinese children are vaccinated with DTaP at ages 3, 4, and 5 months as the primary schedule and receive a booster dose at 18 months. There is no booster vaccine for preschool children, adolescents, or pregnant women. In a recent study among children in Shenzhen, China, 37·1% of children admitted to hospital with pertussis were younger than 3 months (appendix p 1) and 55·7% of unvaccinated children with pertussis were too young to receive any dose of vaccine.4Zhang JS Wang HM Yao KH et al.Clinical characteristics, molecular epidemiology and antimicrobial susceptibility of pertussis among children in southern China.World J Pediatr. 2020; 16: 185-192Crossref PubMed Scopus (8) Google Scholar Bringing the first of the three doses of vaccine against pertussis forwards to age 2 months and adding a booster vaccination not only at age 18 months but also at age 5–6 years might reduce the incidence and mortality of pertussis in young infants in China. Cocooning strategies and strategies targeting pregnant women cannot easily be carried out in China due to costs and potential associated stigma. The Comment by T Alex Perkins and Quan Minh Tran5Perkins TA Tran QM Timing is everything when it comes to pertussis vaccination.Lancet Infect Dis. 2021; (published online Oct 18.)https://doi.org/10.1016/S1473-3099(21)00353-4Summary Full Text Full Text PDF PubMed Scopus (1) Google Scholar mentioned that a series of two to three doses of vaccine administered to infants must be carefully timed. Pertussis vaccines are commonly delayed by minor illness such as a cold, and with such delays good protection would also be delayed. In a study from Shenzhen in children older than 5 months up to age 4 years, 40·0% had not received any pertussis vaccine, even though according to guidance they should have had at least three primary doses.4Zhang JS Wang HM Yao KH et al.Clinical characteristics, molecular epidemiology and antimicrobial susceptibility of pertussis among children in southern China.World J Pediatr. 2020; 16: 185-192Crossref PubMed Scopus (8) Google Scholar In addition to the immunisation schedule, the pertussis vaccines used in the national immunisation programme in China, co-purified acellular vaccines, have been shown to induce lower levels of anti-pertussis toxin IgG than separately purified acellular vaccines.6Zhang Z Pan J Chen M Zhang T Li J Lu L Seroepidemiology of pertussis in China: a population-based, cross-sectional study.Vaccine. 2021; 39: 1687-1692Crossref PubMed Scopus (1) Google Scholar The programme should therefore use separately purified acellular pertussis vaccines. We declare no competing interests. JZ and JD contributed equally. Download .pdf (.11 MB) Help with pdf files Supplementary appendix Effect of change in vaccine schedule on pertussis epidemiology in France: a modelling and serological studyA shorter-lived protection induced by the new vaccine schedule recommended in France since 2013 is associated with an increase of pertussis cases in children aged 2–5 years. If similar findings are observed in other countries and clinical trials, these findings should be considered in future pertussis vaccination policies. Full-Text PDF