Safety and immunogenicity of a diphtheria, tetanus, acellular pertussis and Haemophilus influenzae Type b combination vaccine compared with separate administration of licensed equivalent vaccines in Chinese infants and toddlers for primary and booster immunization

Burden of whooping cough in China (PertussisChina): study protocol of a prospective, population-based case-control study

INTRODUCTION

Pertussis is one of the top 10 diseases of children under 10 years of age, and the few vaccine-preventable diseases who is on a rise in China in recent years; however, the true burden of pertussis, including age-stratified incidence and risk factors of severe sequelae, are under-recognised. We aim to estimate the health burden of laboratory-confirmed pertussis by age groups, considering the setting of illness onset (ie, in community, outpatient and inpatient), in a Chinese population (~2.23 million in total) at two sites.

METHODS AND ANALYSIS

This paper describes the study design of a 1-year, prospective, age-stratified and population-based case-control study, including site selection, study population, case registry, ascertainment and enrolment, control recruitment, follow-up of case, microbiological methods, data collection, quality control activities and statistical methods used to generate incidence estimates. During June 2021 through May 2022, registry of suspected pertussis cases (namely chronic/persistent cough) will be conducted in several participating hospitals (SHs) at the two sites, which are selected based on Healthcare Utilisation and Attitudes Surveys (HUAS) carried out before study initiation. A case-control study will be conducted in the SHs and we aim to enrol a total of 1000 suspected pertussis cases (ie, all hospital admissions and the first 1-3 outpatient visits each week each hospital) and 2000 frequency matched healthy controls in community. Our primary study outcome, the laboratory-confirmed Bordetella pertussis infection, will be determined by a comprehensive laboratory methods and procedures (ie, culture, PCR and serological tests) in both cases and controls at enrolment and during 60-day's follow-up visits. Finally, data from HUAS (ie, population size), case registry (ie, the total number of suspected pertussis cases) and case-control study (ie, the prevalence or population attributable fraction of Bordetella pertussis) will be combined to calculate incidence and its 95% CI through bootstrap method. Epidemiological analyses will be conducted to determine the risk factors associated with severe sequelae of pertussis.

ETHICS AND DISSEMINATION

This study has been approved by Chinese Centre for Disease Control and Prevention's Institutional Review Board (no. ICDC-202110). Results will be disseminated via academic presentations and publication in peer-reviewed journals, and will provide valuable scientific data and some new insights into the incidence, aetiology and risk factors for severe sequelae of pertussis to academic societies and the public health authorities who is currently struggling and fighting against this burdensome disease worldwide.

Surveillance on the adverse events following immunization with the pentavalent vaccine in Zhejiang, China

Objectives

The aim of this study is to describe the reporting rate of adverse events following immunization (AEFI) with pentavalent vaccine: diphtheria-pertussis-tetanus-poliomyelitis-Haemophilus influenzae type b (DPT-IPV/Hib), and to determine whether the reporting rate of AEFI following DPT-IPV/Hib was higher than the average level of the other vaccines.

Methods

Review and describe the AEFI reported to national adverse event following immunization surveillance system (NAEFISS) in Zhejiang province from 2015 to 2020. Reporting rates of AEFI were calculated by age, city, severity of AEFI, categories of AEFI, and reaction categories. The data mining algorithm used in this study was reporting odds ratio (ROR). A value of ROR‑1.96SE >1 (standard error [SE]) was considered as positive signal.

Results

NAEFISS received 5726 AEFI reports following DTP-IPV/Hib, with a reporting rate of 20.01/10000 doses. Of the reported AEFI, 202 were serious vaccine product-related reactions, including two cases of anaphylactic shock, five cases of Guillain Barre Syndrome (GBS) and two cases of acute disseminated encephalomyelitis. The reporting rate of fever/redness/induration was the highest among all the clinical diagnosis (14.97/10000 doses). The positive signals were obtained for allergic rash (ROR-1.96SE: 1.36), febrile convulsion (ROR-1.96SE: 1.32) and GBS (ROR-1.96SE: 1.16).

Conclusion

The present findings bolstered that the DTP-IPV/Hib administered as the four-dose schedule was generally well tolerated in Chinese infants as we did not identify any new/unexpected safety concern from the NAEFISS during a six-year timespan.

Immunogenicity of a Candidate DTacP-sIPV Combined Vaccine and Its Protection Efficacy against Pertussis in a Rhesus Macaque Model

The research and development of a pertussis-combined vaccine using a novel inactivated poliovirus vaccine made from the Sabin strain (sIPV) is of great significance in the polio eradication project and to address the recent resurge in pertussis. In the present study, we compared the immunogenicity and efficacy of a candidate DTacP-sIPV with those of a commercial DTacP-wIPV/Hib, DTaP/Hib, pertussis vaccine, and aluminum hydroxide adjuvant control in the rhesus macaque model with a 0-, 1-, and 2-month immunization schedule. At day 28 after the third dose, rhesus macaques were challenged with aerosol pertussis and the antibody and cellular response together with pertussis clinical symptoms were determined. The production of anti-PT, anti-PRN, anti-FHA, anti-DT, anti-TT, and polio type I, II, III antibodies was induced by the candidate DTacP-sIPV, which was as potent as commercial vaccines. In comparison with the control group that showed typical pertussis symptoms of humans after the aerosol challenge, the DTacP-sIPV group did not exhibit obvious clinical pertussis symptoms and had higher neutralization titers of anti-PT, anti-PRN, and anti-FHA. In conclusion, the DTacP-sIPV vaccine was able to induce immunity in rhesus macaques to prevent pertussis infections after immunization. The developed vaccine was as efficient as other commercial vaccines.

Safety, immunogenicity and persistence of immune response to the combined diphtheria, tetanus, acellular pertussis, poliovirus and Haemophilus influenzae type b conjugate vaccine (DTPa-IPV/Hib) administered in Chinese infants

We conducted 3 phase III, randomized, open-label, clinical trials assessing the safety, reactogenicity (all studies), immunogenicity (Primary vaccination study) and persistence of immune responses (Booster study) to the combined diphtheria, tetanus, pertussis, poliomyelitis, and Haemophilus influenzae type b vaccine (DTPa-IPV/Hib) in Chinese infants and toddlers.

In the Pilot study (NCT00964028), 50 infants (randomized 1:1) received 3 doses of DTPa-IPV/Hib at 2–3–4 (Group A) or 3–4–5 months of age (Group B). In the Primary study (NCT01086423), 984 healthy infants (randomized 1:1:1) received 3 doses of DTPa-IPV/Hib at 2–3–4 (Group A) or 3–4–5 (Group B) months of age, or concomitant DTPa/Hib and poliomyelitis (IPV) vaccination at 2–3–4 months of age (Control group); 825 infants received a booster dose of DTPa/Hib and IPV at 18–24 months of age (Booster study; NCT01449812).

In the Pilot study, unsolicited symptoms were more frequent in Group A (16 versus 1 infant; mostly upper respiratory tract infection and pyrexia); this observation was attributed to an epidemic outbreak of viral infections. Non-inferiority of 3-dose primary vaccination with DTPa-IPV/Hib over separately administered DTPa/Hib and IPV was demonstrated for Group A (primary objective). Similar antibody concentrations were observed in all groups, except for anti-polyribosyl-ribitol phosphate and anti-poliovirus types 1–3 which were higher in DTPa-IPV/Hib recipients. Protective antibody levels against all vaccine antigens remained high until booster vaccination. Three-dose vaccination with DTPa-IPV/Hib had a clinically acceptable safety profile.

Safety and immunogenocity of a novel combined Haemophilus influenzae type b-Neisseria meningitidis serogroups A and C-tetanus-toxoid conjugate vaccine in healthy Chinese children aged 6 months to 5 years old

A novel combined Haemophilus influenzae type b-Neisseria meningitidis serogroups A and C-tetanus-toxoid conjugate vaccine (Hib-MenAC vaccine) has been developed to protect children against diseases caused by Hib, MenA, and MenC. This study investigated the safety and immunogenicity of the Hib-MenAC vaccine administered in 2-dose series to children aged 6-23 months and in a single dose to children aged 2-5 y. A randomized, positive-controlled, non-inferiority clinical trial was conducted for 1200 healthy participants in each age group. Within each age group, participants were randomly allocated to the Hib-MenAC group or the control group at a ratio of 1:1. Adverse reactions were recorded within 28 d after each dose. Blood samples were obtained to assess immunogenicity on day 0 and at 28 d after a complete vaccination course. For the investigational vaccine, the incidence of total adverse reactions in vaccinees aged 6-23 months was 46.8% and that in vaccinees aged 2-5 y was 29.8%. Most adverse reactions were mild or moderate. One non-fatal serious adverse event occurred in the Hib-MenAC group, but was unrelated to vaccination. The seroconversion rate to the 3 components reached 94.0%, and the proportion of vaccinees with rSBA titers ≥ 1:8 and PRP ≥ 0.15 g/mL reached 97.0% in both age groups. The safety and immunogenicity of the Hib-MenAC vaccine were non-inferior when compared to the licensed vaccines. It was concluded that the novel vaccine would be expected to protect children against all of the targeted diseases.