The COVID-19 pandemic is a global emergency threatening to take millions of lives in the United States and around the world. There is no current vaccine strategy against COVID-19 infection caused by a novel coronavirus named SARS-CoV-2. Studies with a related coronavirus called SARS-CoV-1 that caused the SARS outbreak in 2003 indicated that memory CD8+ T cells recognizing viral epitopes persisted for more than 6 years post infection while neutralizing antibodies and memory B cells were short-lived and were undetectable after a short period of time (Tang et al., 2011; Peng et al., 2006; Channappanavar et al., 2014). Thus, including viral epitopes that are recognized by memory CD8+ T cells is imperative for vaccines that can provide long-term immunity against SARS-CoV-2. In this study, blood samples from COVID-19 patients who have recovered from the infection will be used to identify the viral epitopes recognized by their memory CD8+ T cells. This will be accomplished using a genome-wide, high-throughput screening technology developed at Harvard Medical School (Kula et al., 2019) and licensed by the study sponsor, TScan Therapeutics. A 24,000-member library that tiles across all ~100 viral isolates of SARS-CoV-2 that have been sequenced so far has already been synthesized at TScan. Blood samples from convalescent patients are urgently needed to identify T cell receptors and immunogenic viral epitopes on SARS-CoV-2. It is the hope that these data will inform development of a vaccine with the potential for long-lasting protection against SARS-CoV-2.

Inclusion Criteria:

• Laboratory-confirmed diagnosis of COVID-19 performed by The Centers for Disease Control and Prevention (CDC) at a hospital using an FDA Emergency Use Authorized molecular assay for COVID-19
• Age =>18 years at time of diagnosis of COVID-19
• Time since discontinuation of isolation of =>14 day following CDC criteria
• Ability to understand and willingness to sign an informed consent document
• No anti-pyretic use for =>17 days
• Ability to undergo blood draw for 4 tubes of blood containing approximately 7.5 mL of blood each
• Ability to travel to an assigned lab for blood draw
• Ability to waive any claim to blood samples or data obtained for this study's purpose

Exclusion Criteria:

• Any serious medical or psychiatric disorder that would interfere with the subject's safety
• Dementia, altered mental status, or any psychiatric condition that would prohibit the understanding or rendering of informed consent
• Known blood disorder that would increase the risk of infection or bleeding from a simple phlebotomy

COVID-19 convalescents previously hospitalized willing to donate blood. Both men and women and members of all races and ethnic groups are eligible for this protocol. It is expected that the mix of participants entering this study will reflect the demographics of the population affected by COVID-19.