Citrus fruits, vitamin D, and the RNA virus: A correlation and meta-analysis study in Taiwan and the USA

•RNA viruses are significant threats to the world's public health.•It is anticipated that vitamin D will have strong immunomodulatory effects by suppressing the replication of RNA virus in the host.•Citrus fruits and their secondary metabolites have the power to boost antibodies against RNA viruses.•The effects of both Citrus fruits along with its secondary metabolites and Vitamin D were compared with the research and review articles available across the USA and Taiwan. The main threat to human health is infectious disease. For the treatment of infections with RNA viruses, there are hardly any antiviral drugs in the market. This is especially concerning because RNA viruses continue to generate the majority of emerging and highly pathogenic viruses, and this trend is expected to continue. The use of phytochemicals in alternative therapies for viral infections is essential. Bioactive compounds of citrus are widely employed to treat a wide range of viral diseases, and calciferol (vitamin D) has been shown to have virucidal effects. According to various researchers from around the world such bioactive chemicals from citrus, along with calciferol, have the potential to have both an inhibitory and a complementary therapeutic effect against RNA viruses. The purpose of this research is to find the therapeutic effects of vitamin D and citrus fruit to minimize RNA virus virulence by comparing the data and analyzing and by reviewing it and the data collected from the research/ review papers of Taiwan and the United States. Utilizing specified keywords and logical expressions, intensive online searches of pertinent open-access literature found in high-quality and dependable databases served as the foundation for the layout of this review study. Mostly this review is focused on the data of citrus fruit and vitamin d against RNA virus and compared the data from each country. The data information that is available in this paper suggests that consuming enough vitamin D and secondary metabolites from citrus fruits are linked to a much lower risk of contracting RNA virus infections.