It is the initial type of pertussis vaccine given in infancy – acellular or whole cell – that primes the immune system and determines how soon adolescents become susceptible to pertussis, regardless of later acellular booster vaccination, noted the authors of a new study.
In this study, Dutch children received acellular pertussis, diphtheria, and tetanus (DTaP) vaccine or whole-cell pertussis, diphtheria, and tetanus (DTwP) vaccine at ages 2, 3, 4, and 11 months. The researchers determined the IgG subclass distribution against the pertussis, diphtheria, and tetanus vaccine antigens before and after a DTaP booster vaccination at about age 4 years and an additional Tdap booster vaccination at about age 9 years.
The IgG4 subclass proportion for IgG4-specific antibodies remained lower in patients who had whole-cell pertussis (wP) priming in infancy, even though they had received acellular pertussis booster vaccinations at ages 4 and 9 years, compared with patients who underwent acellular pertussis (aP) priming in infancy. This was true for all vaccine antigens, other than filamentous hemagglutinin and tetanus, 1 year after the preadolescent booster, noted researcher Saskia van der Lee of the National Institute for Public Health and the Environment, Bilthoven, The Netherlands, and her associates.
“With higher vaccine antigen-specific IgG1/IgG4 ratios, wP-primed children may have a better protection against pertussis infection, compared to aP-primed children, even after booster vaccinations. This is in line with epidemiological data indicating that adolescents, after aP vaccination in infancy, are more susceptible to pertussis, compared with wP-primed adolescents, though wP-primed individuals become also susceptible over time,” the researchers said.
In addition, children primed with DTwP vaccines have a more Th1-skewed response for pertussis vaccine antigens after receiving a DTap booster vaccine or clinical infection with Bordetella pertussis, whereas children primed with DTaP have a more mixed pertussis-specific Th1/Th2 response, the researchers said. So “new adjuvants that skew the immune response towards a Th1 profile are desired” for better protection against pertussis over time.
SOURCE: van der Lee S et al. Vaccine. 2018 Jan 4;36(2):220-6.