Surveillance for adverse events following immunization with DTaP-containing combination vaccines in Linping, China, 2019-2022.

Background: The DTaP-Hib and DTaP-IPV/Hib combination vaccine can be used as a substitute for the diphtheria, tetanus, and acellular pertussis combined vaccine (DTaP). We aimed to evaluate the safety of multi-component vaccines containing DTaP by analyzing the reporting rates and characteristics of adverse events following immunization (AEFIs) in Linping District during the years 2019 to 2022. Methods: We obtained data of AEFI and vaccination from the National AEFI Surveillance System of China and Zhejiang Municipal Immunization Information Management System, respectively, during 2019-2022 for a descriptive, epidemiological analysis. Results: The total number of AEFI reported following vaccinations with DTaP-containing combination vaccines was 802 in Linping District from 2019 to 2022. The overall reporting rates of AEFIs following DTaP, DTaP-Hib, and DTaP-IPV/Hib vaccinations were 445.72 (537 cases), 536.29 (45 cases), and 306.13 (220 cases) per 100,000 doses in Linping District from 2019 to 2022, respectively. Only one case of a serious AEFI following DTaP vaccination, with a reporting rate of 0.83 per 100,000 doses. The composition ratio of vaccine product-related reactions for DTaP, DTaP-Hib, and DTaP-IPV/Hib were 99.81, 97.78, and 100.00%, respectively. The composition ratio of coincidental events for DTaP and DTaP-Hib were 0.19 and 2.22%, respectively. The reporting rates of total AEFIs for DTaP-IPV/Hib were lower than for DTaP. The reporting rate of local induration for DTaP-Hib was lower than for DTaP, and the reporting rates of local redness & swelling and local induration for DTaP-IPV/Hib were both lower than for DTaP. DTaP-IPV/Hib had a higher proportion of AEFIs in first quarter compared to DTaP. The reporting rate after the second dose of DTaP-Hib was higher than that of DTaP, and the reporting rates of AEFIs after the first dose and third dose of DTaP-IPV/Hib were lower than DTaP. Conclusion: The reported AEFIs to multi-component vaccines containing DTaP components during 2019-2022 in Linping District were mainly mild vaccine reactions. DTaP-containing combination vaccines demonstrated a good safety profile.

Genetic predisposition to adverse events in Chinese children aged 3-24 months after diphtheria, tetanus, acellular pertussis and haemophilus influenzae type b combined vaccination.

BACKGROUND: Post-vaccination safety is a major public health concern. The genetic predisposition on immune response has not been clearly identified. Clarifying whether individual genetic predisposition plays a role on adverse events (AEs) is critical for the prevention of AEs. METHODS: From July 2019 to June 2020, we performed a case-control study among children aged 3-24 months in seven Chinese provinces. Each child received a combination vaccination against diphtheria, tetanus, acellular pertussis, and Haemophilus influenzae type b (DTaP-Hib). Through daily telephone follow-up, we collected AEs within seven days. Oral swab samples were collected to investigate the effects of single nucleotide polymorphisms (SNPs) on the risk of AEs. RESULTS: 304 participants were included in the study. In univariate analysis, we discovered three protective SNPs (rs452204, OR = 0.67, P = 0.0352; rs9282763 and rs839, OR = 0.64, P = 0.0256) and one risk SNP (rs9610, OR = 2.20, P = 0.0397). In multivariate analysis, the effects of rs452204 and rs839 were found to be stable. The interaction between rs452204 and rs9610 was observed (OR = 7.25, 95% CI: 1.44-36.58, P = 0.0165). CONCLUSION: Genetic predisposition was associated with the risk of AEs after DTaP-Hib vaccination, emphasizing the potential application in the prevention of AEs.

Monitoring of adverse reaction of Haemophilus influenzae type b vaccine in Songjiang District， Shanghai / 上海预防医学

ObjectiveTo determine the reporting rate of adverse reaction of Haemophilus influenzae type b （Hib） containing vaccine in Songjiang District from 2016 to 2020， so as to provide evidence for the inclusion of Hib vaccine in children's immunization planning and safety monitoring. MethodsThe adverse reaction data of Hib vaccination were collected through the Chinese Disease Prevention and Control Information System and presented by descriptive methods. ResultsFrom 2016 to 2020， the reporting rate of adverse reaction of various Hib-containing vaccines in Songjiang District was determined to be 747.76/105 doses， among which the rates of general reaction and abnormal reaction were 734.31/105 doses and 13.45/105 doses， respectively. The reporting rate of general reaction was significantly higher than that of abnormal reaction （χ2=1 400.18，P<0.001）. Moreover， the reporting rate of adverse reaction did not differ significantly by sex or registered residence， whereas it differed significantly by age groups （χ2=366.07，P<0.001）. Children ≥12 months old had the highest reporting rate， which was caused by higher rate of general reaction （χ2=360.48，P<0.001） compared with other age groups； in contrast， there was no difference in the reporting rate of abnormal reactions across age groups. The reporting rate of adverse reaction differed significantly across four Hib-containing vaccines （χ2=508.51，P<0.001）， among which the reporting rate of pentavalent vaccine was the highest， followed by tetravalent vaccine， and Hib vaccine and meningococcal HI vaccine. This difference was mainly caused by general reaction （χ2=499.19，P<0.001）. The reporting rate of booster Hib-containing vaccines was significantly higher than that of basic immunization （χ2=462.85，P<0.001）. Furthermore， the reporting rate differed between DTaP-Hib vaccine and DTaP-IPV-Hib vaccine by injection sites（χ2=13.63，P=0.001；χ2=78.48， P<0.001）； the reporting rate on the thigh was lower than that on the hip or upper arm. Among the 1 501 reported adverse reactions， 97.21% of the general reactions and 85.19% of the abnormal reactions occurred within 72 hours following immunization. Principal clinical diagnosis was fever， redness and nodules （n=1 454）， accounting for 96.87% of the total reported adverse event following immunization（AEFI）， followed by allergic rash. ConclusionThe four types of Hib-containing vaccines have high safety. Health care practitioners at points of vaccination should improve the pre-examination， standardized operation and full notification in strict accordance with the requirements. It also warrants strengthening the AEFI monitoring， investigation and response， so as to effectively reduce the incidence and severity of adverse reactions.