Use of a combined acellular vaccine against pertussis infection in children over four years of age: a cross-sectional study

An increase in the incidence of whooping cough has been noted in recent years in both unvaccinated and vaccinated children and adults. In Russia, recently, new possibilities of protection against pertussis infection have appeared for children over four years old and adults. Purpose: to analyze the specific immunoprophylaxis and safety of the vaccine against diphtheria, tetanus and pertussis for children over four years old in Krasnodar. Materials and methods. We examined 393 children over four years and 125 adults who were immunized with a vaccine for the prevention of diphtheria (with a reduced antigen content), tetanus, pertussis (acellular), combined, adsorbed (Adasel) at the SKIB city hospital in Krasnodar in the period from July 2018 until October 2019. The respondents had a vaccination history and did not suffer from whooping cough, according to medical records. Results. The number of people vaccinated with acellular vaccine doubled among the child population (2018 - 129; 2019 - 264) and adults (2018 - 39; 2019 - 86). General post-vaccination reactions among children amounted to 12.2% (48), weak responses prevailed - 36 (9.2%), strong responses were found in 12 people (3%). In adults, general post-vaccination responses were not observed. Local post-vaccination reactions among children amounted to 38.2% (150), weak reactions prevailed - 103 (26.2%), strong ones were found in 47 children (12%). Conclusions. During the study period, immunoprophylaxis with this vaccine doubled, showing a satisfactory safety profile. However, to reduce the incidence of whooping cough, it is advisable to examine the immunological protection and conduct revaccination with a booster dose to achieve stable post-vaccination immunity.

Fha Deficient Bordetella pertussis Isolates in Iran with 50 Years Whole Cell Pertussis Vaccination

Background: Bordetella pertussis, a highly contagious respiratory. Notably, the resurgence of pertussis has recently been associated with the lacking production of vaccine virulence factors. This study aimed to screen pertactin (Prn) and filamentous hemagglutinin (Fha) production in Iran with 50 years' whole cell vaccine (WCV) immunization program. Methods: Overall, 130 B. pertussis isolates collected from Pertussis Reference Laboratory of Iran during 2005-2018. Real-time PCR was performed by targeting IS481, ptxP, IS1001 and IS1002 for species confirmation of B. pertussis. Western-blot was used to evaluate the expression of virulence factors (pertactin and filamentous hemagglutinin). Results: All tested B. pertussis isolates expressed Prn and all except two isolates expressed Fha. We have sequenced genomes of these strains and identified differences compared with genome reference B. pertussis Tohama I. Conclusion: Many countries reporting Prn and Fha-deficiency due to acellular vaccine (ACV) pressure. Our results demonstrate in a country with WCV history, Fha-deficient isolates may rise independently. However, Prn-deficient isolates are more under the ACV pressure in B. pertussis isolates. Continues surveillance will provide a better understanding of the effect of WCV on the evolution of the pathogen deficiency.

Vaccine-driven selection and the changing molecular epidemiology of Bordetella pertussis

Pertussis remains one of the least controlled vaccine-preventable diseases despite high vaccine coverage in many countries. There are ongoing debates about the causes of its resurgence. Major changes have occurred in the Bordetella pertussis population since the introduction of vaccination. Currently circulating strains in Australia and many other developed countries are grouped in single nucleotide polymorphism (SNP) cluster I (also known as ptxP3 strains). The emergence and expansion of SNP cluster I has been associated with two major genetic changes in B. pertussis: a change in its pertussis toxin promoter (to ptxP3) which leads to increased pertussis toxin production and the change of the acellular vaccine pertactin gene allele to prn2. More recently, strains that lack pertactin have emerged independently in different lineages. The resurgence of pertussis in highly vaccinated populations can be, at least in part, explained by genetic changes that increase the fitness of circulating B. pertussis strains.

Response to Comment on “The impact of past vaccination coverage and immunity on pertussis resurgence”

We present new evidence that the immunity conferred against pertussis by the DTaP acellular vaccine wanes more slowly than widely believed.