Does infection with SARS-CoV 2 induce lasting immunity?Posted on by
Although we expect, based on basic immunology, that there will be some degree of immunity after recovery from a primary infection, there is currently no evidence that people who have antibodies to SARS-CoV-2 are fully protected from a second infection.
I. WHO Scientific Brief from April 24, 2020 (1):
- They are still reviewing evidence on antibody responses to SARS-CoV-2 infections
- Most studies show that people who have recovered from SARS-CoV-2 have antibodies to the virus, however; no human study has evaluated whether the presence of antibodies confers full immunity to subsequent infections (one study in recovered monkeys showed no symptoms when reinfected with an identical strain )
- They caution that current antibody testing needs to be improved to assure that the tests accurately distinguish between past SARS-CoV-2 infection and infections with previously known Coronaviruses which circulate widely in humans
- Presence of antibodies does not guarantee immunity at this time
II. Media Reports:
- There have been reports of previously infected individuals retesting positive for SARS-CoV-2 or having symptoms again in South Korea (3) , China (4), and British Columbia (5), however; these are very sparse in relation to total infected individuals and experts are uncertain if they are true reinfections, testing discrepancies, or if individuals weren’t truly recovered
- While experts don’t have enough evidence now to speak definitively on the issue, we can look at past infections of coronaviruses to predict what type of antibody response may be imparted by SARS-CoV-2 (6)
- 4 other types of coronaviruses produce the common cold and antibody presence may last about 1 year (7)
- 2 types produce the more severe SARS and MERS epidemics, with the SARS antibody studies suggesting antibodies could last 1-2 years (8) with markedly reduced antibodies at the 3 year mark (9) and no antibodies found at the 6 year mark (10)
- MERS antibody studies suggested that longevity of the antibodies is correlated with severity of disease (more severely ill patients had antibodies present 18 months post infection while patients with mild symptoms had no antibodies at 18 months post infection )
- These studies looked at presence or absence of antibodies, not whether people could become reinfected with the virus should they come in contact with it
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- World Health Organization: WHO. “Immunity passports” in the context of COVID-19 [Internet]. Who.int. World Health Organization: WHO; 2020 [cited 2020 Apr 29]. Available from: https://www.who.int/news-room/commentaries/detail/immunity-passports-in-the-context-of-covid-19
- Bao L, Deng W, Gao H, Xiao C, Liu J, Xue J, et al. Reinfection could not occur in SARS-CoV-2 infected rhesus macaques. 2020 Mar 14 [cited 2020 Apr 29]; Available from: https://www.biorxiv.org/content/10.1101/2020.03.13.990226v1
- South Korea says recovered COVID-19 patients re-testing positive [Internet]. CBC. 2020 [cited 2020 Apr 29]. Available from: https://www.cbc.ca/news/world/south-korea-coronavirus-covid19-reactivated-positive-1.5529066
- Stanway D. Explainer: Coronavirus reappears in discharged patients, raising questions in containment fight [Internet]. U.K. Reuters; 2020 [cited 2020 Apr 29]. Available from: https://uk.reuters.com/article/us-china-health-reinfection-explainer/explainer-coronavirus-reappears-in-discharged-patients-raising-questions-in-containment-fight-idUKKCN20M124
- Rankin E, Paisley Woodward. COVID-19 relapse or reinfection? The mysterious case of Shilan Garousi, hit twice by coronavirus [Internet]. CBC. 2020 [cited 2020 Apr 29]. Available from: https://www.cbc.ca/news/canada/british-columbia/covid-19-relapse-or-reinfection-1.5546771
- Gallagher J. Coronavirus immunity: Can you catch it twice? BBC News [Internet]. 2020 Apr 27 [cited 2020 Apr 29]; Available from: https://www.bbc.com/news/health-52446965
- Callow, Parry, Sergeant, Tyrrel. The time course of the immune response to experimental coronavirus infection of man: Epidemiol Infect [Internet]. 1990;105:435–46. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2271881/pdf/epidinfect00023-0213.pdf
- Liu W, Fontanet A, Zhang P, Zhan L, Xin Z, Baril L, et al. Two‐Year Prospective Study of the Humoral Immune Response of Patients with Severe Acute Respiratory Syndrome. The Journal of Infectious Diseases [Internet]. 2006 Mar 15 [cited 2020 Apr 29];193(6):792–5. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7109932/
- Wu L-P, Wang N-C, Chang Y-H, Tian X-Y, Na D-Y, Zhang L-Y, et al. Duration of Antibody Responses after Severe Acute Respiratory Syndrome. Emerging Infectious Diseases [Internet]. 2007 Oct [cited 2020 Apr 10];13(10):1562–4. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2851497/
- Tang F, Quan Y, Xin Z-T, Wrammert J, Ma M-J, Lv H, et al. Lack of peripheral memory B cell responses in recovered patients with severe acute respiratory syndrome: a six-year follow-up study. Journal of immunology (Baltimore, Md : 1950) [Internet]. 2011 [cited 2020 Apr 29];186(12):7264–8. Available from: https://www.ncbi.nlm.nih.gov/pubmed/21576510
- Alshukairi AN, Khalid I, Ahmed WA, Dada AM, Bayumi DT, Malic LS, et al. Antibody Response and Disease Severity in Healthcare Worker MERS Survivors. Emerging Infectious Diseases. 2016 Jun;22(6).
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