Varicella vaccine (live) powder and solvent for suspension for injection 0.5ml vials

BackgroundThis study provides a comprehensive review of studies comparing the effectiveness of varicella vaccinations and the duration of their protection.MethodsWe conducted a systematic literature review to identify comparative studies evaluating the effectiveness of the varicella vaccine. A meta-analysis was performed to assess the effectiveness of one-dose and two-dose vaccinations, as well as the outcomes for moderate and severe illness, and the duration of protection, using random effects models.ResultsOut of 66 studies, 57 reported the effectiveness of a single-dose varicella vaccine, 28 examined the two-dose vaccination, and 25 focused on effectiveness against moderate to severe disease. Of these, 59 were observational studies and 7 were trials. Thirteen studies reported the duration of protection. The overall vaccine effectiveness for a single dose was 79% (76-82%; I² = 97.2%), while for two doses, it was 94% (93-96%; I² = 90.8%). The overall effectiveness against moderate or severe illness was 92% (90-94%; I² = 90.3%). The duration of protection showed a slight decline over time. Evidence suggests that both one and two doses of the varicella vaccine offer short-term protection, though this protection wanes rapidly.ConclusionThe two-dose vaccination demonstrated superior clinical efficacy compared to the one-dose vaccination, with protection slightly diminishing over time. These findings highlight the importance of implementing universal two-dose varicella vaccination programs in countries.Trial registrationPROSPERO Identifier: CRD42024589864.

Abstract licence: CC BY-NC

ObjectivesThis study aimed to synthesize existing evidence to compare the immunogenicity and safety of domestic and imported live-attenuated varicella vaccine (VarV) in healthy Chinese populations.MethodsWe searched PubMed, Web of Science, Embase, China National Knowledge Internet (CNKI), Wan Fang Database, and Chinese Biomedical Literature Service System (SinoMed) using predefined search terms to identify relevant studies. Retrieve all language articles up to March 15, 2024. Articles reported varicella vaccination in healthy Chinese populations were included. We calculated the pooled rates of seroconversions and adverse events using the random effects model and assessed the quality of each study using the modified Jadad Scale and Newcastle Ottawa Scale (NOS). Publication bias was evaluated using Egger's regression test.ResultsIn our immunogenicity analysis, which included 16,655 Chinese individuals from 21 studies, the pooled seroconversion rate was 89% (95%CI: 86-91%) for domestic VarV and 93% (95%CI: 88-98%) for imported Varv, with no statistically significant difference. In our safety analysis, which included 29,696 Chinese individuals from 25 studies, the pooled rate of systemic reactions was higher for domestic Varv (11%, 95%CI: 10-13%) than for imported Varv (8%, 95%CI: 6-10%; P ConclusionsBoth domestic and imported varicella vaccines appear to be generally immunogenic and safe in healthy Chinese populations. However, due to limited and heterogeneous data on imported vaccines, further high-quality studies are needed to validate these comparative findings.

Abstract licence: CC BY-NC-ND