METHODS: A test-negative case-control design estimated vaccine effectiveness against symptomatic disease and hospitalization due to SARS-CoV-2. HCWs who underwent PCR or antigen testing for SARS-CoV-2 from January 2021 to March 2022 were included. Cases had a positive diagnostic test, while controls had negative tests. Adjusted vaccine effectiveness (aVE) was calculated using the formula: aVE = (1 - Odds ratio) × 100.
RESULTS: During the Delta variant\'s predominance, aVE against infection within 12-120 days post-second dose was 64.8 % (BNT162b2) and 59.4 % (mRNA-1273), declining to 21.2 % and 42.2 %, respectively, after 120 days. For the Omicron variant, aVE within 12-120 days post-second dose was 61.1 % (BNT162b2) and 85.1 % (mRNA-1273), decreasing to 36.7 % and 24.9 %, respectively, after 120 days. After a booster dose of mRNA-1273, aVE was 64.0 % (BNT162b2 recipients) and 65.9 % (initial mRNA-1273 recipients). Regardless of variant, aVE for hospitalization prevention after 2 doses was 87.0 % (BNT162b2) and 89.0 % (mRNA-1273).
CONCLUSIONS: The administration of two doses of Moderna-mRNA-1273 against SARS-CoV-2 in HCWs proved to be highly effective in preventing infections and hospitalizations in the first 120 days after the second dose during the predominance of the Omicron variant. The decline in VE after 120 days since the administration of the second dose was significantly restored by the booster dose administration. This increase in VE was greater for the Pfizer vaccine. COVID-19 hospitalization prevention remained stable with both mRNA vaccines throughout the study period.
方法:试验阴性病例对照设计评估了疫苗对SARS-CoV-2引起的症状性疾病和住院的有效性。包括从2021年1月至2022年3月接受SARS-CoV-2PCR或抗原测试的HCWs。病例诊断试验呈阳性,而对照组的检测结果为阴性。使用公式:aVE=(1-赔率比)X100计算调整的疫苗有效性(AVE)。
结果:在Delta变体占主导地位期间,在第二次剂量后12-120天内针对感染的AVE为64.8%(BNT162b2)和59.4%(mRNA-1273),下降到21.2%和42.2%,分别,120天后对于Omicron变体,第二剂量后12-120天内的AVE为61.1%(BNT162b2)和85.1%(mRNA-1273),下降到36.7%和24.9%,分别,120天后在mRNA-1273的加强剂量后,aVE为64.0%(BNT162b2受体)和65.9%(初始mRNA-1273受体)。不管是什么变体,2剂后用于住院预防的AVE为87.0%(BNT162b2)和89.0%(mRNA-1273)。
结论:在HCWs中,针对SARS-CoV-2的两剂Moderna-mRNA-1273的给药被证明可以非常有效地预防感染和住院。在Omicron变体占主导地位的第二剂量后的前120天。自第二剂量施用后120天后VE的下降通过加强剂量施用显著恢复。对于辉瑞疫苗,VE的增加更大。在整个研究期间,两种mRNA疫苗的COVID-19住院预防保持稳定。