Effectiveness Associated With Vaccination After COVID-19 Recovery in Preventing Reinfection

Abstract

Key Points Question How effective is vaccination against COVID-19 after recovery from prior SARS-CoV-2 infection? Findings In this cohort study of more than 95 000 Rhode Island residents from March 2020 to December 2021, including residents and employees of long-term congregate care (LTCC) facilities, completion of the primary vaccination series after recovery from COVID-19 was associated with 49% protection from reinfection among LTCC residents, 47% protection among LTCC employees, and 62% protection in the general population during periods when wild type, Alpha, and Delta strains of SARS-CoV-2 were predominant. Meaning These findings suggest that among people who have recovered from COVID-19, subsequent completion of the primary vaccination series reduced the risk of reinfection by approximately half.

COVID-19 vaccines reduce the risk of SARS-CoV-2 reinfection and hospitalization: Meta-analysis

“…Of the 3,470 papers initially retrieved, seven case-control (4, 21-26) and 11 cohort studies (6)(7)(8)(27)(28)(29)(30)(31)(32)(33)(34) were included in the analyses (Supplementary Figure 1 and Supplementary Table 1). Three studies contributed with two dataset (24,27,31), as the same publication provided separate data for healthcare workers and the general population (31), and for Delta and Omicron waves (24,27): this led to a total of 21 datasets that were included in the analyses (Table 1).…”

“…The methodological characteristics of the included studies are summarized in Table 2: the selection of the cohort of patients, the ascertainment of the exposure, and the evaluation of the comparability of subjects were adequate in all studies, while 15 out of 18 adequately addressed the items pertaining to outcome assessment and follow-up (length and missing data). Twenty-one datasets including a total of 18,132,192 individuals were included in the overall meta-analysis comparing the risk of SARS-CoV-2 reinfection in vaccinated vs. unvaccinated subjects (Table 3) (4,(6)(7)(8)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34). In 20 out of 21 datasets, the vaccinated subjects were significantly less likely to be reinfected, with a summary OR of 0.47 (95% confidence interval-CI -0.42-0.54) (Figure 1).…”

“…Compared with the unvaccinated, those receiving ≥ 1 dose were significantly less likely to develop a severe disease, once reinfected (OR: 0.45; 95% CI: 0.38-0.54-Table 3 and Figure 2). The risk remained comparably and Three studies (24,27,31) contributed with more than one dataset, thus the number of references does not always match the number of datasets included in each analysis (see "Results" for further details). significantly lower when only the subset of studies evaluating partial vaccination (OR: 0.35; 95% CI: 0.21-0.60) or those evaluating full vaccination (OR: 0.34; 95% CI: 0.24-0.49) vs. no vaccination, were included.…”

“…Six studies were carried out in Europe ( 4 , 6 , 8 , 24 , 27 – 29 ), six in the USA ( 21 , 22 , 24 – 26 , 31 ), five in Asia ( 7 , 30 , 32 – 34 ) and one in South Africa ( 23 ). Thirteen studies evaluated the general population ( 4 , 6 – 8 , 21 , 22 , 24 – 28 , 30 , 31 ), and six assessed the healthcare workers ( 23 , 29 , 31 – 34 ).…”

A study of the prevalence of COVID-19 among students of the Syrian Private University.

“…Individuals who have recovered from COVID-19 and are still unvaccinated should be encouraged to complete the remainder of the vaccine doses, as they are eligible, to reduce the risk of reinfection. (22) Recommendations 1. Conducting a study that includes a larger sample number to accurately study the symptoms among students.…”