Department of Virology, Professor Alborzi Clinical Microbiology Research Center, Namazi Hospital, Shiraz University of Medical Sciences, Shiraz, 71937-11351, Iran.
Department of Family Medicine and Infectious Disease, Shiraz University of Medical Sciences, Shiraz, Iran.
Virol J. 2023 Aug 18;20(1):182. doi: 10.1186/s12985-023-02156-2.
BACKGROUND/AIMS: The aim of this study was to determine the rate of natural and breakthrough infection and related symptoms of Covid-19 amongst Iranian healthcare workers (HCWs) who were vaccinated by different non-mRNA-based vaccines at peak points.
In this cross-sectional study, the RT-PCR test was performed for a total of 10,581 HCWs suspicious of Covid-19 infection. For each HCW, the frequency of SARS-CoV-2 infection and the time of transmission based on vaccination administration time and schedule were examined during different waves of the pandemic. Based on these findings, the study patients were divided into three groups: natural, natural/breakthrough, and breakthrough.
In total, 53% of the HCWs were exposed to SARS-CoV-2 infection between 1 and 5 times within two years after the current pandemic, while 20.7% and 32.3% experienced natural and breakthrough SARS-CoV-2 infection, respectively. Only 6% of the breakthrough-infected HCWs had naturally contracted SARS-CoV-2 infection during the initial waves. The highest natural peaks of infection occurred during the interval administration of the first and second dose of the first vaccination series, while the single highest peak of breakthrough infection belonged to the Omicron wave. It occurred simultaneously with the administration of the third vaccination dose. On the other hand, the highest rate of reinfection was observed amongst people who had received the Sinopharm and Bharat vaccines full-doses.
This study compared the clinical differences between the two peaks of Omicron and Delta. This study indicates the rates of natural and breakthrough SARS-CoV-2 infections according to vaccination schedules and different waves of the pandemic.
背景/目的：本研究旨在确定在疫情高峰期接种不同非 mRNA 疫苗的伊朗医护人员（HCWs）中 COVID-19 的自然感染和突破性感染率及相关症状。
在这项横断面研究中，对总共 10581 名疑似 COVID-19 感染的 HCWs 进行了 RT-PCR 检测。对于每一位 HCW，根据疫苗接种时间和时间表，检查了在不同疫情波次中 SARS-CoV-2 感染的频率和传播时间。基于这些发现，将研究患者分为三组：自然感染、自然/突破性感染和突破性感染。
在两年内，共有 53%的 HCWs 被 SARS-CoV-2 感染了 1-5 次，其中 20.7%和 32.3%分别经历了自然和突破性 SARS-CoV-2 感染。只有 6%的突破性感染 HCWs 在初始波次中自然感染过 SARS-CoV-2。自然感染的最高峰发生在第一剂和第二剂第一针接种系列间隔期间，而突破性感染的单一最高峰则属于奥密克戎波次。它与第三剂疫苗接种同时发生。另一方面，全剂量接种国药和 Bharat 疫苗的人群中，再感染率最高。
本研究比较了奥密克戎和德尔塔两个高峰的临床差异。本研究根据疫苗接种计划和不同的疫情波次，显示了自然和突破性 SARS-CoV-2 感染的发生率。
