The authors read and approved the final manuscript. Funding Nil. Availability of data and materials Not applicable. Declarations Ethical approval and consent to participateNot relevant. Consent for publicationNot applicable. Competing interestsThe authors declare that they have no competing interests. Footnotes Publishers Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Contributor Information Chinonyerem O. was used to Nylidrin Hydrochloride assess risk of bias in individual studies. The evaluate was conducted in line with Preferred Regulatory Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines 2009. From your 952 studies screened and 2 studies from reference hand-searching, 18 were reviewed. Four studies evaluated the risks for SARS-CoV-2 contamination among RAAS inhibitors users, and 16 (including 2 of the 4 studies) evaluated the clinical outcomes associated with previous exposure to RAAS Nylidrin Hydrochloride inhibitors. Conclusion Evidence does not suggest higher risks for SARS-CoV-2 contamination or poor disease prognosis in the use of RAAS inhibitors. This suggests the continued use of RAAS inhibitors by patients with existing needs, which supports the position statements of American Heart Association and European societies for Cardiology. Supplementary Information The online version contains supplementary material available at 10.1186/s43094-021-00224-4. = 0.556) (Table ?(Table1).1). The experts also found that ACEI/ARB use was not significantly associated with severe clinical outcomes of COVID-19 (OR 0.79; CI 0.26C1.95; = 0.629). The experts however, advised caution in interpreting Nylidrin Hydrochloride the lack of statistical significance, sighting the small sample size as a possible factor. The retrospective study was conducted among 154 patients in 2 nursing homes in Belgium, and data were collected from March 1 to April 16, 2020. The analysis included adjustment for covariates which were age, sex, comorbidities and functional status. Although the study comprised a small sample size, it draws attention to the effects of ACEIs/ARBs around the older populace with COVID-19. Table 1 Characteristics of the studies = 0.65), with survivours and non-survivours (27.3% vs 33.0%; = 0.34). The duration of retrospective data collection was moderate, but the study was carried out in a single centre. Therefore, replications with a randomized study design in a larger populace will provide better evaluation of these associations. It is noteworthy that patients who were exposed to ACEIs/ARBs were not comparably matched with others in this study. Furthermore, another retrospective study conducted in China , among 511 COVID-19 patients with focus on the elderly ( 65 years old), observed ARB use prior to hospitalization to be significantly associated with decrease in severity as compared with patients who experienced no history of antihypertensive drug therapy. Data from Itga1 patients who Nylidrin Hydrochloride were admitted between December 29, 2019 and February 29, 2020 were analyzed for the study. Other antihypertensive drug groups also analyzed were persons who required calcium channel blockers, beta blockers, thiazides and ACE inhibitors. The experts also performed a meta-analysis using 3 previous studies, and findings suggest that ACEIs/ARBs may be associated with decreased pneumonia-related mortality. Although, encouraging findings are seen in this study particularly for the elderly, it should be noted that this potential for bias from cofounders is not unlikely. Also, analysis for significant differences was not carried out for some groups of antihypertensive drug users due to small sample size. Another study in the USA  involved a much larger, older populace and reported the absence of significant relationship with the use of ACEI/ARB and hospitalization/rigorous care in COVID-19. Data from a secure health record was collected retrospectively for any cohort of 2,026,227, from which 585 (15.4% of 3789 persons who tested positive) COVID-19 cases of 54C75 years old were studied. ACE/ARB users composed 40.5% of analyzed cases. These findings are suggestive of the continued use of these classes of drugs for clinical needs, even in high-risk COVID-19 communities. Meanwhile, the design of this study.