“Ask an Ethicist” is a new SGIM Forum department that provides answers to questions in clinical ethics posed by SGIM members. Members of the SGIM Ethics Committee respond to real ethics cases and questions submitted by SGIM members. Responses are created with input from the Committee but do not necessarily reflect the views of the Committee or SGIM. To submit a case or question, visit: https://www.sgim.org/communities/other-sgim-committees/ethics/ask-an-ethicist.


A patient presents for an acute care appointment with a physician she has never seen before to request a letter allowing her to return to work. The patient tested positive for COVID-19 one month ago after having symptoms including rhinorrhea and cough. She has been on sick leave from work since she developed symptoms, and she is now asymptomatic. The patient works at a nursing home that has recently instituted a COVID-19 vaccine mandate for its workers, but she says she is unwilling to receive a COVID-19 vaccine under any circumstances. She asks the physician to write a letter stating that she may safely return to work. Should the physician provide this letter to the patient?


As vaccine mandates become more common in workplaces throughout the United States, general internists might encounter cases such as this one: an unvaccinated worker, subject to a mandate, requests a return-to-work letter. Our response should be guided by both scientific considerations and ethical principles of autonomy, beneficence, and justice, following from our commitment to promote the good of individual patients as well as the common good.

At first glance, this patient’s question seems straightforward: guidelines have consistently recommended that isolation is no longer medically indicated for asymptomatic patients who tested positive weeks ago. A physician might simply clear her to return safely to work and avoid addressing the mandate altogether, allowing the patient to negotiate that issue with her employer. However, some internists may believe that such a letter requires a statement on the patient’s desire to be exempted from the nursing home’s mandate.

At the individual patient level, the science regarding “natural immunity,” which develops as a patient recovers from COVID-19 infection, informs this question. Some evidence suggests that natural immunity protects against subsequent infection as well as vaccines do,1, 2 even in patients whose symptoms were mild.3, 4 Other evidence suggests reinfection with COVID-19 is more common in the unvaccinated, and that natural immunity may vary among individuals and wane over time.4, 5 However, much of the currently available evidence is in flux or awaiting peer review, leaving clinicians to make decisions under profound uncertainty.

Based on the above-cited evidence, it seems reasonable to conclude that convalescent patients, at least within the first few months after a COVID-19 infection, have at least as much protection against infection as vaccinated individuals do.6 At the individual level, a requirement that naturally immune patients also receive a COVID-19 vaccine seems to demand greater immunity of them than it does of vaccinated individuals, a double standard. However, vaccine mandates may eventually require fully vaccinated individuals to receive boosters to further improve their immunity or research may show that natural immunity wanes or does not reduce transmission. Under any of these conditions, it would be equitable to require convalescent patients to increase their immunity as well by receiving a vaccine.

This case also involves potentially competing ethical concerns. Respect for this patient’s autonomy means allowing her to refuse the vaccine. In terms of beneficence to her, individually, one could also argue that vaccination simply exposes her to very rare risks of vaccination (such as myocarditis and thrombosis) without any corresponding benefit, since she already has sufficient immunity. This line of argument suggests the possibility of exemption for those with recent COVID-19 infections; in fact, some countries, such as Israel, do not require vaccination for six months following infection.4 Without permission to return to work, this patient may also be harmed by losing her job, leaving the nursing home short staffed.

One might point out that the physician and patient have a social obligation in justice to take steps to protect the residents and other employees in the nursing home. Yet, we lack evidence to suggest that this individual patient’s risk of getting re-infected and transmitting COVID-19 to the nursing home residents is higher than that of vaccinated workers, whose protection appears to wane over time.7 No doubt physicians have a duty to promote COVID-19 vaccination generally, but that obligation does not override the physician’s primary obligation to the individual patient.

A clinician seeing this patient might begin by carefully and sensitively inquiring about the reasons behind the patient’s hesitancy. Unfortunately, an acute care visit with a new physician is not an ideal setting for such a discussion. Ideally, a patient’s primary care provider should consider writing the letter only after a careful dialogue that addresses the potential benefits of vaccination for this patient. Of course, not all patients have a PCP or can access their providers within the timeframe demanded by their employers in certain cases.

If I were seeing a patient who had established with a colleague in my own practice, I would be willing to provide a letter. In such circumstances I am acting in some sense on their PCP’s behalf, and I think the practice has an obligation to meet patients’ needs. However, I would decline to write such a letter if I were working in a detached urgent care facility that provided no continuity of care.

In my opinion, it would be ethically acceptable to write a letter supporting this patient’s ability to return to work safely, provided she complies with all the other protective measures, such as mask-wearing, in effect at her workplace. I would recommend testing the patient’s serum for the presence of COVID-19 IgG antibodies to confirm prior to writing the letter that she in fact had COVID-19. Given the uncertainty of the available scientific evidence, I would also recommend using careful language in the letter, stating that it would be reasonable to allow the patient to return to work now but taking no position on whether vaccination will eventually be necessary. Although my analysis focuses on this physician-patient relationship, I would also note that there is another agent involved in this case, namely the patient’s workplace. Whereas the physician has a fiduciary duty to promote the good of the individual patient in alignment with the common good, healthcare administrators have more direct responsibility for the common good of their workers and the patients they serve. This perspective may understandably lead them to deny the patient’s request to return to work, even with a letter from the physician. In this brief response, I take no position on which exemptions to vaccine mandates administrators are obligated to grant.


  1. Gazit S, Shlezinger R, Perez G, et al. Comparing SARS-CoV-2 natural immunity to vaccine-induced immunity: Reinfections versus breakthrough infections.  medRxiv. Accessed December 15, 2021.
  2. Shrestha NK, Burke PC, Nowacki AS, et al. Necessity of COVID-19 vaccination in previously infected individuals. medRxiv. Accessed December 15, 2021.
  3. Turner JS, Kim W, Kalaidina E, et al. SARS-CoV-2 infection induces long-lived bone marrow plasma cells in humans. Nature. 2021;595(7867):421-425.
  4. Block J. Vaccinating people who have had COVID-19: Why doesn’t natural immunity count in the US? BMJ. 2021;374:n2101.
  5. Cavanaugh AM, Spicer KB, Thoroughman D, et al. Reduced risk of reinfection with SARS-CoV-2 after COVID-19 Vaccination – Kentucky, May-June 2021. MMWR Morb Mortal Wkly Rep. 2021;70(32):1081-1083.
  6. Levin EG, Lustig Y, Cohen C, et al. Waning Immune Humoral Response to BNT162b2 COVID-19 vaccine over 6 months. N Engl J Med. Published October 6, 2021. doi:10.1056/NEJMoa2114583.
  7. Bergwerk M, Gonen T, Lustig Y, et al. COVID-19 breakthrough infections in vaccinated health care workers. N Engl J Med. 2021;385(16):1474-1484.



Clinical Practice, COVID-19, Health Policy & Advocacy, Medical Education, Medical Ethics, SGIM

Author Descriptions

Dr. Karches (kyle.karches@health.slu.edu) is chair of the SGIM Ethics Committee and an associate professor of internal medicine and healthcare ethics at Saint Louis University.