COVID-19: SARS-CoV-2 Reinfection not a serious large-scale threat to natural immunity

By Peter A. McCullough, MD, MPH, Baylor University Medical Center, Dallas TX

There is considerable attention on the potential to be infected a second or third or fourth time with SARS-CoV-2 and be hospitalized over and over again with COVID-19.  Thankfully, at over 110 million cases worldwide, we have not seen thousands of rehospitalizations.  In fact, reports of possible recurrence are very rare, yet are used as public health rationale for COVID-19 recovered patients to undergo vaccination with its intendant risks including death. 

A recent case from France reported that a 58-year-old man had a brief illness with a positive SARS-CoV-2 nasal PCR test in September 2020 and then was infected with the South African variant 501Y.V2 strain in January 2021 and was hospitalized and required mechanical ventilation.[1]  Although details are not given, when the nasal PCR test is run at cycle thresholds >35 ct, the test picks up pieces of RNA in the nasal secretions from influenza and other viral fragments.  Since the patient is 58 and has asthma, the September illness was almost certainly not COVID-19, since in a man his age and with asthma COVID-19 will last for 14 to 30 days or more.   His first and real COVID-19 illness occurred in January 2021. 

In another report from the SIREN study in England, researchers reported 44 cases defined as having two positive PCR tests 90 days apart or a positive PCR test 4 weeks after having positive serologies.[2]  In this report, among those with “probable” infection there was only 1 case age ~41 who had COVID-19 symptoms for 14 days with the background of having positive serology, not a second illness.  This study had mainly healthcare workers that have many exposures to patients and can have positive serologies from those exposures, and in this case develop their first infection.  Selvaraj and coworkers reported a case where the nasal PCR was positive in an asymptomatic man over age 70 in April 2020 and twelve days later he was treated in the emergency department for what appeared to be a community acquired pneumonia and discharged home.[3]  Seven months later when his family contracted COVID-19, the patient is admitted to the hospital with COVID-19 supported by SARS-CoV-2 nasal PCR and other laboratory testing, x-rays, and is treated as a COVID-19 patient in-hospital.  Selvaraj reports 34 additional cases in a table and stated: “There have been other case reports of reinfections where patients have also remained mostly asymptomatic or shown decreased symptom severity” and details are not given for each case, it is very likely that these cases are similar misinterpretations of false positive nasal PCR testing. 

The key point is that severe COVID-19 is a clinical syndrome, and the public and medical community should be immediately suspicious of any declared reinfection.  Since there have been 110 million cases worldwide, it is either a false positive PCR situation or it is extraordinarily rare and probably a mild self-limited illness.   There is absolutely no call for vaccination in COVID-19 recovered patients on the basis of these spurious reports.  Natural immunity appears to be complete and durable and far superior to what has been reported thus far with vaccination.


[1] Zucman N, Uhel F, Descamps D, Roux D, Ricard JD. Severe reinfection with South African SARS-CoV-2 variant 501Y.V2: A case report. Clin Infect Dis. 2021 Feb 10:ciab129. doi: 10.1093/cid/ciab129. Epub ahead of print. PMID: 33566076.

[2] Hall V, Foulkes S, Charlett A, et al. Do antibody positive healthcare workers have lower SARS-CoV-2 infection rates than antibody negative healthcare workers? Large multi-centre prospective cohort study (the SIREN study), England: June to November 2020. 14 January 2021. https://www.medrxiv.org/content/10.1101/2021.01.13.21249642v1.full.pdf

[3] Selvaraj V, Herman K, Dapaah-Afriyie K. Severe, Symptomatic Reinfection in a Patient with COVID-19. R I Med J (2013). 2020 Nov 9;103(10):24-26. PMID: 33172223.

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