Seroconversion following the first, second, and third dose of SARS-CoV-2 vaccines in immunocompromised population: a systematic review and meta-analysis.

BACKGROUND: Immunocompromised (IC) patients are at higher risk of more severe COVID-19 infections than the general population. Special considerations should be dedicated to such patients. We aimed to investigate the efficacy of COVID-19 vaccines based on the vaccine type and etiology as well as the necessity of booster dose in this high-risk population. MATERIALS AND METHODS: We searched PubMed, Web of Science, and Scopus databases for observational studies published between June 1st, 2020, and September 1st, 2021, which investigated the seroconversion after COVID-19 vaccine administration in adult patients with IC conditions. For investigation of sources of heterogeneity, subgroup analysis and sensitivity analysis were conducted. Statistical analysis was performed using R software. RESULTS: According to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses, we included 81 articles in the meta-analysis. The overall crude prevalence of seroconversion after the first (n: 7460), second (n: 13,181), and third (n: 909, all population were transplant patients with mRNA vaccine administration) dose administration was 26.17% (95% CI 19.01%, 33.99%, I2 = 97.1%), 57.11% (95% CI: 49.22%, 64.83%, I2 = 98.4%), and 48.65% (95% CI: 34.63%, 62.79%, I2 = 94.4%). Despite the relatively same immunogenicity of mRNA and vector-based vaccines after the first dose, the mRNA vaccines induced higher immunity after the second dose. Regarding the etiologic factor, transplant patients were less likely to develop immunity after both first and second dose rather than patients with malignancy (17.0% vs 37.0% after first dose, P = 0.02; 38.3% vs 72.1% after second dose, P < 0.001) or autoimmune disease (17.0% vs 36.4%, P = 0.04; 38.3% vs 80.2%, P < 0.001). To evaluate the efficacy of the third dose, we observed an increasing trend in transplant patients after the first (17.0%), second (38.3%), and third (48.6%) dose. CONCLUSION: The rising pattern of seroconversion after boosting tends to be promising. In this case, more attention should be devoted to transplant patients who possess the lowest response rate.

The effect of COVID-19 mRNA vaccines against postvaccination laboratory-confirmed SARS-CoV-2 infection, symptomatic COVID-19 infection, hospitalization, and mortality rate: a systematic review and meta-analysis.

OBJECTIVES: We systematically reviewed the literature to investigate the pooled effect of COVID-19 mRNA vaccination against SARS-CoV-2 infection and its clinical outcomes. METHODS: Scopus, Web of Science, PubMed (Medline), and Embase were searched on 9 September 2021. The odds ratio (OR) of COVID-19 infection and its clinical outcomes in fully/ partially vaccinated versus unvaccinated participants were calculated and pooled by using a random-effects model. RESULTS: The pooled analysis showed that among health care workers and general population, vaccinated participants with one or two doses were less likely to infect with SARS-CoV-2 (OR = 0.16; 95%CI: 0.08-0.32; I2 = 79.86%; 95%CI I2: 68.99-87.21%), to develop symptomatic COVID-19 infection (OR = 0.09; 95%CI: 0.03-0.32; I2 = 80.43%; 95%CI I2: 70.83-89.33%), to admit to the hospital because of COVID-19 (OR = 0.13; 95%CI: 0.06-0.28; I2 = 86.19%; 95%CI I2: 67.80-93.88%), and to die from COVID-19 (OR = 0.14; 95%CI: 0.06-0.35; I2 = 66.76%; 95%CI I2: 54.00-76.99%) than unvaccinated participants. CONCLUSIONS: COVID-19 mRNA vaccines, especially following administration of two doses, are extremely effective. It would be suggested further studies with large sample size and different ethnicities to be conducted among the general population to warrant these results.

Immunogenicity of COVID-19 mRNA vaccines in immunocompromised patients: a systematic review and meta-analysis.

BACKGROUND: Immunocompromised (IC) patients are at higher risk of severe SARS-CoV-2 infection, morbidity, and mortality compared to the general population. They should be prioritized for primary prevention through vaccination. This study aimed to evaluate the efficacy of COVID-19 mRNA vaccines in IC patients through a systematic review and meta-analysis approach. METHOD: PubMed-MEDLINE, Scopus, and Web of Science were searched for original articles reporting the immunogenicity of two doses of mRNA COVID-19 vaccines in adult patients with IC condition between June 1, 2020 and September 1, 2021. Meta-analysis was performed using either random or fixed effect according to the heterogeneity of the studies. Subgroup analysis was performed to identify potential sources of heterogeneity. RESULTS: A total of 26 studies on 3207 IC patients and 1726 healthy individuals were included. The risk of seroconversion in IC patients was 48% lower than those in controls (RR = 0.52 [0.42, 0.65]). IC patients with autoimmune conditions were 54%, and patients with malignancy were 42% more likely to have positive seroconversion than transplant recipients (P < 0.01). Subgroup meta-analysis based on the type of malignancy, revealed significantly higher proportion of positive seroconversion in solid organ compared to hematologic malignancies (RR = 0.88 [0.85, 0.92] vs. 0.61 [0.44, 0.86], P = 0.03). Subgroup meta-analysis based on type of transplantation (kidney vs. others) showed no statistically significant between-group difference of seroconversion (P = 0.55). CONCLUSIONS: IC patients, especially transplant recipients, developed lower immunogenicity with two-dose of COVID-19 mRNA vaccines. Among patients with IC, those with autoimmune conditions and solid organ malignancies are mostly benefited from COVID-19 vaccination. Findings from this meta-analysis could aid healthcare policymakers in making decisions regarding the importance of the booster dose or more strict personal protections in the IC patients.

Serious events following COVID‐19 vaccination with ChAdOx1 nCoV‐19 vaccine (Vaxzevria): A short case series from Iran

In 2020, the SARS‐COV‐2 disease (COVID‐19) imposed huge challenges on the health, economic, and political systems, and by the end of the year, hope had been born with the release of COVID‐19 vaccines aimed at bringing the pandemic to an end. However, the COVID‐19 vaccination programs have sparked several concerns and ongoing debates over safety issues. Here, we presented three cases of patients with serious adverse events, encephalopathy, vaccine‐induced thrombotic thrombocytopenia, and leukocytoclastic vasculitis, after receiving the ChAdOx1 nCoV‐19 vaccine. Therefore, it is critical to investigate and report the occurrence of adverse reactions following vaccination, particularly serious ones, as it contributes to the growing body of research and assists clinicians in better diagnosing and managing them. Despite the crucial role of COVID‐19 vaccination in controlling the pandemic, occurring of the severe adverse effects following inoculation is also inevitable and should be considered

Serious events following COVID-19 vaccination with ChAdOx1 nCoV-19 vaccine (Vaxzevria): A short case series from Iran.

In 2020, the SARS-COV-2 disease (COVID-19) imposed huge challenges on the health, economic, and political systems, and by the end of the year, hope had been born with the release of COVID-19 vaccines aimed at bringing the pandemic to an end. However, the COVID-19 vaccination programs have sparked several concerns and ongoing debates over safety issues. Here, we presented three cases of patients with serious adverse events, encephalopathy, vaccine-induced thrombotic thrombocytopenia, and leukocytoclastic vasculitis, after receiving the ChAdOx1 nCoV-19 vaccine. Therefore, it is critical to investigate and report the occurrence of adverse reactions following vaccination, particularly serious ones, as it contributes to the growing body of research and assists clinicians in better diagnosing and managing them.