Once cured on Covid-19 can you get infected again?

Family Medicine Specialist

Medcare Medical Center, Al Barsha, Dubai

There is no definitive answer to this question as yet. As studies continue globally to assess whether people who have been cured can contract the infection again or not, it is recommended to take all measures to ensure safety. Here is a highlight on the global discussion on the topic till now.

This topic was first brought up on 13th of April 2020, when 116 recovered cases of COVID-19 in South Korea were reported to have been found positive again. The Korean approach to mark a patient as negative is obtaining 2 negative samples within 24 hours, however more precautions seem to be needed to be sure a patient has truly recovered from COVID-19 or may not reactivate again after recovery.[1]

Immunity development to a pathogen through natural infection is a multi-step process that happens over 1-2 weeks. Response of the body to a viral infection is immediate with a non-specific innate response (macrophages, neutrophils, and dendritic cells slow the viral progression and might prevent it from causing symptoms). This is followed by an adaptive response where the body makes antibodies that specifically bind to the virus. These antibodies are proteins called immunoglobulins. [2]

Kircaldy et al. reported in May 11 2020 that current limited data on the responses of the antibody o SARS-CoV-2 and related coronaviruses, as well as one small animal model study, suggest that recovery from COVID-19 might confer immunity against reinfection, at least temporarily. However, the response of the immune system to COVID-19 is not yet fully understood and definitive data on post infection immunity are lacking.[3]

The WHO is continuing to review the evidence on antibody responses to SARS-CoV-2 infection. Where the majority of theses studies reveal that people who have recovered from infection have antibodies to the virus, however some of these people have very low levels of neutralizing antibodies in their blood,suggesting that cellular immunity may also be critical for recovery. As of 24 April 2020, no study has been able to evaluate whether the presence of antibodies to SARS-CoV-2 confers immunity to subsequent infection by this virus in humans.

[1] Alizargar J. (2020). Risk of reactivation or reinfection of novel coronavirus (COVID-19). Journal of the Formosan Medical Association .Taiwan yi zhi, 119(6), 1123. https://doi.org/10.1016/j.jfma.2020.04.013

[2] WHO: (2020)”Immunity passports” in the context of COVID-19 https://www.who.int/news-room/commentaries/detail/immunity-passports-in-the-context-of-covid-19

[3] Kirkcaldy RD, King BA, Brooks JT. (2020) COVID-19 and Postinfection Immunity: Limited Evidence, Many Remaining Questions. JAMA. Published online May 11, 2020. doi:10.1001/jama.2020.7869