Levels of antibodies specific to diphtheria toxoid, tetanus toxoid, and Haemophilus influenzae type b in healthy children born to Tdap-vaccinated mothers

Antibody persistence to diphtheria toxoid, tetanus toxoid, Bordetella pertussis antigens, and Haemophilus influenzae type b following primary and first booster with pentavalent versus hexavalent vaccines

Thailand has incorporated the whole-cell (wP) pertussis vaccine into the expanded program on immunization since 1977 and has offered the acellular pertussis (aP) vaccine as an optional vaccine for infants since 2001. We followed healthy children from a clinical trial (ClinicalTrials.gov NCT02408926) in which children were randomly assigned to receive either pentavalent (DTwP-HB-Hib) or hexavalent (DTaP-IPV-HB-Hib) vaccines for their primary series (administered at 2, 4, and 6 months) and first booster vaccination (18 months). Both groups received Tdap-IPV as a second booster at the age of 4 y. Blood samples were collected for evaluation of antibody persistence to diphtheria toxoid (DT), tetanus toxoid (TT), and Bordetella pertussis (B. pertussis) between 2 and 6 y of age annually, and for the immunogenicity study of Tdap-IPV at 1 month after the second booster. Antibody persistence to Haemophilus influenzae type b (Hib) was followed until 3 y of age. A total of 105 hexavalent-vaccinated children and 91 pentavalent-vaccinated children completed this study. Both pentavalent and hexavalent groups demonstrated increased antibody levels against DT, TT, and B. pertussis antigens following the second booster with Tdap-IPV. All children achieved a seroprotective concentration for anti-DT and anti-TT IgG at 1 month post booster. The hexavalent group possessed significantly higher anti-pertactin IgG (adjusted p = .023), whereas the pentavalent group possessed significantly higher anti-pertussis toxin IgG (adjusted p < .001) after the second booster. Despite declining levels post-second booster, a greater number of children sustained protective levels of anti-DT and anti-TT IgG compared to those after the first booster.

Immunogenicity of the pentavalent DTwP-HB-Hib vaccine (Shan-5) used in the Thai Expanded Program on Immunization compared to the hexavalent DTaP-HB-Hib-IPV and DTwP-HB-Hib (Quinvaxem) vaccines administered to infants at 2, 4, 6 months of age

BACKGROUND

The pentavalent DTwP-HB-Hib (Shan-5) vaccine was first introduced into the Thailand Expanded Program on Immunization (EPI) in 2019. The Shan-5 vaccine is administered to infants at 2, 4, and 6 months of age, after initial vaccination with monovalent hepatitis B (HepB) and Bacillus Calmette-Guérin (BCG) vaccines at birth. This study compared the immunogenicity of the HepB, diphtheria, tetanus, and Bordetella pertussis antigens incorporated in the EPI Shan-5 vaccine versus the optional pentavalent (DTwP-HB-Hib) Quinvaxem and hexavalent (DTaP-HB-Hib-IPV) Infanrix-hexa vaccine.

METHODS

Three-dose Shan-5-vaccinated children were prospectively enrolled at the Regional Health Promotion Centre 5, Ratchaburi province, Thailand, between May 2020 and May 2021. Blood sampling was performed at months 7 and 18. The levels of HepB surface antibody (anti-HBs), anti-diphtheria toxoid (DT) IgG, anti-tetanus toxoid (TT) IgG, and anti-pertussis toxin (PT) IgG were evaluated using commercially available enzyme-linked immunoassays.

RESULTS

Anti-HBs levels of ≥10 mIU/mL were achieved in 100 %, 99.2 %, and 99.2 % of infants in the Shan-5 EPI group, hexavalent group and Quinvaxem group one month after four dose immunization (at 0, 2, 4, 6 months of age), respectively. The geometric mean concentrations of the EPI Shan-5 and hexavalent groups were comparable but were higher than those of the Quinvaxem group. At one month after primary vaccination (month 7), infants in the Shan-5 EPI group had significantly higher levels of anti-DT IgG, anti-TT IgG, and anti-PT IgG than infants in the hexavalent and Quinvaxem groups.

CONCLUSIONS

The immunogenicity of the HepB surface antigen in the EPI Shan-5 vaccine was similar to that achieved by the hexavalent vaccine, but was higher than that achieved by the Quinvaxem vaccine. The Shan-5 vaccine is highly immunogenic and generates robust antibody responses after primary immunization.

Vaccination coverage in children with juvenile idiopathic arthritis, inflammatory bowel diseases, and healthy peers: Cross-sectional electronic survey data

BACKGROUND

Patients with immune-mediated diseases, such as juvenile idiopathic arthritis (JIA) and inflammatory bowel disease (IBD) are at increased risk of developing infections, due to disease-related immune dysfunction and applying of immunosuppressive drugs.

AIM

To evaluate vaccine coverage in patients with IBD and JIA, and compare it with healthy children.

METHODS

In the cross-sectional study we included the data from a questionnaire survey of 190 Legal representatives of children with JIA (n = 81), IBD (n = 51), and healthy children (HC, n = 58). An electronic online questionnaire was created for the survey.

RESULTS

There were female predominance in JIA patients and younger onset age. Parents of JIA had higher education levels. Employment level and family status were similar in the three studied groups. Patients with JIA and IBD had lower vaccine coverage, without parental rejection of vaccinations in IBD, compare to JIA and healthy controls. The main reason for incomplete vaccination was medical conditions in IBD and JIA. IBD patients had a lower rate of normal vaccine-associated reactions compared to JIA and HC. The encouraging role of physicians for vaccinations was the lowest in JIA patients. IBD patients had more possibilities to check antibodies before immune-suppressive therapy and had more supplementary vaccinations compared to JIA and HC.

CONCLUSION

JIA and IBD patients had lower vaccine coverage compared to HC. Physicians' encouragement of vaccination and the impossibility of discus about future vaccinations and their outcomes seemed the main factors for patients with immune-mediated diseases, influencing vaccine coverage. Further investigations are required to understand the reasons for incomplete vaccinations and improve vaccine coverage in both groups, especially in rheumatic disease patients. The approaches that stimulate vaccination in healthy children are not always optimal in children with immune-mediated diseases. It is necessary to provide personalized vaccine-encouraging strategies for parents of chronically ill children with the following validation of these technics.

Cost-Utility Analysis of Universal Maternal Pertussis Immunisation in Thailand: A Comparison of Two Model Structures

OBJECTIVES

This study aimed to assess the cost-effectiveness of introducing universal maternal pertussis immunisation under the national vaccine programme in Thailand.

METHODS

We conducted a cost-utility analysis from a societal perspective to compare maternal vaccination with (1) TdaP vaccine, (2) Td vaccine and aP vaccine, and (3) Td vaccine only. We constructed two decision-tree models with Markov elements, each following a different clinical pathway, to allow us to examine structural uncertainty. Costs were converted to 2021 Thai Baht (THB) and a discount rate of 3% was applied to health and cost outcomes, with sensitivity analysis at 0% and 6%. Parameter uncertainty was investigated through deterministic and probabilistic sensitivity analysis, with expected value of perfect information analysis.

RESULTS

Maternal pertussis vaccination would avert 27 cases and up to one death per year. The incremental cost-effectiveness ratio (ICER) for adding aP to the maternal immunisation schedule is 2,184,025 THB/QALY and the ICER for replacing maternal Td vaccination with TdaP is 3,198,101 THB/QALY. Maternal pertussis vaccination only becomes favourable in the probabilistic sensitivity analysis at cost-effectiveness thresholds above 6,000,000 THB/QALY, far above the Thai threshold of 160,000 THB/QALY. If incidence is less than 397 cases per 100,000, maternal pertussis vaccination will not be cost-effective in Thailand, within the plausible range for vaccine effectiveness and probability of hospitalisation. Budget impact is dominated by vaccination costs, which represent 12% and 18% of the 2021 national vaccine programme budget for introducing aP vaccine or for switching Td with TdaP vaccine, respectively.

CONCLUSIONS

We have found that maternal pertussis immunisation is not cost-effective in Thailand. Although there may be substantial under-reporting of pertussis cases, comparison with hospital data suggests that most under-reported cases are not hospitalised and therefore have negligible impact on our results. However, considerations such as affordability and local manufacturing may also be important for national immunisation programme decision-making.

Whole-cell pertussis vaccine in early infancy for the prevention of allergy in children

BACKGROUND

Atopic diseases are the most common chronic conditions of childhood. The apparent rise in food anaphylaxis in young children over the past three decades is of particular concern, owing to the lack of proven prevention strategies other than the timely introduction of peanut and egg. Due to reported in vitro differences in the immune response of young infants primed with whole-cell pertussis (wP) versus acellular pertussis (aP) vaccine, we systematically appraised and synthesised evidence on the safety and the potential allergy preventive benefits of wP, to inform recommendation for future practice and research.

OBJECTIVES

To assess the efficacy and safety of wP vaccinations in comparison to aP vaccinations in early infancy for the prevention of atopic diseases in children.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials, Ovid MEDLINE, Embase, and grey literature. The date of the search was 7 September 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and non-randomised studies of interventions (NRSIs) that reported the occurrence of atopic diseases, and RCTs only to assess safety outcomes. To be included studies had to have at least six months follow-up, and involve children under 18 years old, who received a first dose of either wP (experimental intervention) or aP (comparator) before six months of age.

DATA COLLECTION AND ANALYSIS

Two review authors independently screened studies for eligibility, extracted the data, and assessed risk of bias using standard Cochrane methods. We assessed the certainty of the evidence using GRADE. Our primary outcomes were diagnosis of IgE-mediated food allergy and all-cause serious adverse events (SAEs). Secondary outcomes included: diagnosis of not vaccine-associated anaphylaxis or urticaria, diagnosis of asthma, diagnosis of allergic rhinitis, diagnosis of atopic dermatitis and diagnosis of encephalopathy. Due to paucity of RCTs reporting on the atopic outcomes of interest, we assessed a broader outcome domain (cumulative incidence of atopic disease) as specified in our protocol. We summarised effect estimates as risk ratios (RR) and 95% confidence intervals (CI). Where appropriate, we pooled safety data in meta-analyses using fixed-effect Mantel-Haenszel methods, without zero-cell corrections for dichotomous outcomes.

MAIN RESULTS

We identified four eligible studies reporting on atopic outcomes, representing 7333 children. Based on a single trial, there was uncertain evidence on whether wP vaccines affected the risk of overall atopic disease (RR 0.85, 95% CI 0.62 to 1.17) or asthma only (RR 1.04, 95% CI 0.59 to 1.82; 497 children) by 2.5 years old.Three NRSIs were judged to be at serious or critical risk of bias due to confounding, missing data, or both, and were ineligible for inclusion in a narrative synthesis.  We identified 21 eligible studies (137,281 children) that reported the safety outcomes of interest. We judged seven studies to be at high risk of bias and those remaining, at unclear risk.  The pooled RR was 0.94 for all-cause SAEs (95% CI 0.78 to 1.15; I² = 0%; 15 studies, 38,072 children). For every 1000 children primed with a first dose of wP, 11 had an SAE. The corresponding risk with aP was 12 children (95% CI 9 to 13). The 95% CI around the risk difference ranged from three fewer to two more events per 1000 children, and the certainty of the evidence was judged as moderate (downgraded one level for imprecision). No diagnoses of encephalopathy following vaccination were reported (95% CI around the risk difference - 5 to 12 per 100,000 children; seven primary series studies; 115,271 children). The certainty of the evidence was judged as low, since this is a serious condition, and we could not exclude a clinically meaningful difference.

AUTHORS' CONCLUSIONS

There is very low-certainty evidence that a first dose of wP given early in infancy, compared to a first dose of aP, affects the risk of atopic diseases in children. The incidence of all-cause SAEs in wP and aP vaccinees was low, and no cases of encephalopathy were reported. The certainty of the evidence was judged as moderate for all-cause SAEs, and low for encephalopathy. Future studies should use sensitive and specific endpoints of clinical relevance, and should be conducted in settings with high prevalence of IgE-mediated food allergy. Safety endpoints should prioritise common vaccine reactions, parental acceptability, SAEs and their potential relatedness to the dose administered.

The vaccine coverage and vaccine immunity status and risk factors of non-protective levels of antibodies against vaccines in children with juvenile idiopathic arthritis: cross-sectional Russian tertiary Centre study

BACKGROUND

Immunosuppressive drugs, incomplete vaccine coverage, immune system dysregulation might be factors of a low level of anti-vaccine antibodies in JIA patients. The study aimed to evaluate vaccine coverage, post-vaccine immunity, and risk factors of non-protective levels of antibodies against measles, mumps, rubella, hepatitis B, and diphtheria in JIA patients.

METHODS

A cross-sectional study included 170 children diagnosed with JIA aged 2 to 17 years who received routine vaccinations against measles, rubella, mumps (MMR), diphtheria, and hepatitis B national vaccine schedule. In all patients, the levels of post-vaccination antibodies (IgG) for measles, rubella, mumps, hepatitis B, and diphtheria were measured with ELISA.

RESULTS

Protective level of antibodies were 50% against hepatitis B, 52% - diphtheria, 58% - measles, 80% - mumps, 98% rubella. MMR's best coverage had patients with enthesitis-related arthritis-85%, compared to oligoarthritis-70%, polyarthritis-69%, systemic arthritis-63%. Diphtheria coverage was 50, 51, 46, 63%, respectively. Incomplete MMR vaccination had 39% patients, treated with biologics, 22% with methotrexate and 14% with NSAID (p = 0.025), and 61, 46, 36% for diphtheria (p = 0.021). Incomplete vaccination was a risk factor of non-protective level of antibodies against measles (HR = 2.03 [95%CI: 1.02; 4.0], p = 0.042), mumps (HR = 6.25 [95%CI: 2.13; 17.9], p = 0.0008) and diphtheria (HR = 2.39 [95%CI: 1.18; 4.85], p = 0.016) vaccines, as well as JIA category, biologics, corticosteroids and long-term methotrexate treatment for distinct vaccines. One-third part of JIA patients continued vaccination against MMR and diphtheria without serious adverse events and JIA flare. There were no differences between patients who continued MMR vaccination or denied in the means of JIA category and treatment options. Patients, continued diphtheria vaccination rare received methotrexate (p = 0.02), biologics (p = 0.004), but had higher levels of anti-diphtheria antibodies (p = 0.024) compare who omitted vaccination. Methotrexate (OR = 9.5 [95%CI: 1.004; 90.3]) and biologics (OR = 4.4 [95%CI: 1.6; 12.1]) were predictors of omitted diphtheria revaccination.

CONCLUSION

Children with JIA may have lower anti-vaccine antibody levels and required routine checks, especially in children with incomplete vaccination, biologics, systemic arthritis, and long-term methotrexate treatment. Revaccination of JIA patients was safe and effective.