Background Tumor necrosis factor-alpha (TNFɑ) is a cytokine that manages the host defense mechanism, which may play a role in the pathogenesis of COVID-19 patients. Several single-nucleotide polymorphisms, described in the promoter region of the TNFα gene, have a significant role on its transcriptional activity. These include the − 308A > G polymorphism which increases the TNFα levels with the expression of the A allele. The aim of this study was to explore whether the TNFα.− 308A > G polymorphism affects the clinical state of COVID-19 patients. The study included a total of 1028 individuals infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which were distributed in 3 groups: asymptomatic, mild symptomatic and severe symptomatic patients. The amplification-refractory mutation system was used to determine the genotype of the TNFα.− 308A > G polymorphism. Results Results show a higher tendency of being asymptomatic in individuals carrying the GG genotype (336 of 411; OR 1.24, 95% CI 0.91–1.70). The development of a severe form of SARS-CoV-2 infection was not found in subjects with the A allele compared to those with the G allele (OR 0.96, 95% CI 0.51–1.79), except in the eastern region of the country where the risk increased (OR 4.41, 95% CI 1.14–17.05). However, the subjects carrying the A allele had a higher chance of developing symptoms (OR 1.24, 95% CI 0.91–1.70) compared to those with the G allele. Conclusion The TNFα.− 308A allele has an influence on developing symptoms of COVID-19 in Cuban patients, and that it particularly increases the risk of presenting severe forms of the disease in the eastern region of the country.