Division of Geriatric and Intensive Care Medicine, Careggi Hospital and University of Florence, Florence.
Geriatric Unit, Santa Maria Annunziata Hospital, Local Health Unit "Toscana Centro", Florence, Italy.
J Am Geriatr Soc. 2022 May;70(5):1336-1341. doi: 10.1111/jgs.17773. Epub 2022 Apr 4.
SARS-CoV-2 vaccination has significantly reduced infection, hospitalization, and lethality rates among nursing home (NH) residents, but durability of vaccine effects remains unknown. This study investigated the long-term impact of BNT162b2 SARS-CoV-2 vaccine on breakthrough infection rates in the NHs of Florence, Italy.
Participants included residents living in Florence NHs as of April 1st, 2021, who had completed the primary SARS-CoV2 vaccination course by February 15th, 2021. Weekly rates of breakthrough infection were calculated between April 1st and October 31st 2021, with 7-day incidence defined as the number of new confirmed SARS-CoV-2-positive residents over the vaccinated resident census. Hospital admissions and deaths were recorded from local administrative and clinical sources. Patients admitted to NHs after April 1st were excluded to avoid confounding effect of different vaccination timing.
Among 2271 vaccinated residents (mean age 86.6, 74% female), we recorded 105 cases of breakthrough infections. Rates of breakthrough infection remained very low in the 6 months after vaccination, but started to rise over the following months, peaking at 0.94%, and then became stable around 0.2%-0.3%. Over the study period, infection rates remained low as compared to the incidence of SARS-CoV-2 infection during pre-vaccination period. Overall hospitalization and lethality rates were 8%.
Among vaccinated NH residents, rates of breakthrough SARS-CoV-2 infection, hospitalization and lethality remained low up to 9 months following primary vaccination course. A mild resurgence of SARS-CoV-2 infection, after 6 months from vaccination, suggests a decline of vaccine effectiveness in preventing transmission.
SARS-CoV-2 疫苗接种显著降低了养老院（NH）居民的感染、住院和死亡率，但疫苗效果的持久性仍不清楚。本研究调查了 BNT162b2 SARS-CoV-2 疫苗对意大利佛罗伦萨 NH 中突破性感染率的长期影响。
参与者包括截至 2021 年 4 月 1 日居住在佛罗伦萨 NH 的居民，他们在 2021 年 2 月 15 日前已完成了 SARS-CoV2 基础疫苗接种。2021 年 4 月 1 日至 10 月 31 日期间，每周计算突破性感染率，7 天发病率定义为接种疫苗居民人数中新确诊的 SARS-CoV-2 阳性居民人数。住院和死亡病例从当地行政和临床来源记录。为避免不同疫苗接种时间的混杂效应，排除 4 月 1 日后入住 NH 的患者。
在 2271 名接种疫苗的居民（平均年龄 86.6 岁，74%为女性）中，我们记录了 105 例突破性感染病例。接种疫苗后 6 个月内，突破性感染率仍很低，但随后几个月开始上升，峰值为 0.94%，然后稳定在 0.2%-0.3%左右。在研究期间，感染率与接种前 SARS-CoV-2 感染的发病率相比仍然较低。总体住院率和死亡率为 8%。
在接种疫苗的 NH 居民中，在基础疫苗接种后 9 个月内，SARS-CoV-2 突破性感染、住院和死亡率仍保持较低水平。接种疫苗后 6 个月，SARS-CoV-2 感染出现轻度反弹，表明疫苗预防传播的效力下降。
