Immunogenicity of two doses of inactive COVID-19 vaccine and third booster dose mRNA vaccine in patients with cancer receiving active systemic therapy.

We aimed to evaluate the seroconversion rates after two doses of inactive COVID-19 vaccine (CoronaVac) and the benefit of a third dose mRNA vaccine booster in patients with cancer receiving active treatment. Patients with solid tumors receiving active treatment (n = 101) and patients with no-cancer (n = 48) as the control group were included in the study. All the patients and controls had received two doses of CoronaVac and a third booster dose of the mRNA vaccine (Bnt162b2). Anti-SARS-CoV-2 Spike Receptor Binding Domain IgG antibody levels after the second and third dose were measured with quantitative ELISA. The median age of the patients was 66 (IQR 60-71). 79% of the patients were receiving chemotherapy, and 21% were receiving immunotherapy at the time of vaccination. Antibody levels measured after two doses of CoronaVac were significantly lower in patients with cancer than in the control group (median 0 µg/ml [IQR 0-1.17 µg/ml] vs median 0.91 µg/ml [IQR 0-2.24 µg/ml], respectively, P = .002). Seropositivity rates were 46.5% in patients with cancer and 72.9% in the control group (P = .002). Antibody measurement was performed in 26 patients after the third dose. Seroconversion rate increased from 46.5% to 88.5% (P < .001), and the antibody titers significantly increased with the third-dose booster (median 0 µg/ml [IQR 0-1.17 µg/ml] after two doses vs 12.6 µg/ml [IQR 1.8-69.1 µg/ml] after third booster dose, P < .001). Immunogenicity of CoronaVac is low in patients with cancer receiving active treatment, and administering a third dose of an mRNA vaccine is effective in terms of improving seroconversion rates.

Hepatitis A susceptibility parallels high COVID-19 mortality.

Background/aim: COVID-19 has become the biggest health problem of this century. It has been hypothesized that immunity against hepatitis A virus (HAV) may provide protection from COVID- 19. Materials and methods: As of 10June 2020, the infection had spread to 213 countries, with 7.3 million people infected and 413,733 dead. This data was combined with the World Health Organization susceptibility classification on the worldwide prevalence of HAV, and the relationship between HAV susceptibility and COVID-19 mortality were analyzed. Results: When the data from 213 countries were analyzed, it was found that there was a significant increasing trend in COVID-19 mortality rates by HAV susceptibility (P <0.001). Using a cut-off of 200/million population, the mortality risk associated with living in a more susceptible country (medium/high) was 27.8 times higher (95% CI for OR: 3.6­213.2) Conclusion: The results of this study showed that, despite confounding factors in different countries, hepatitis A susceptibility of the population may have been correlated with COVID-19 mortality. This observation needs to be confirmed by further studies.