Whither immunity? The search for effective, durable immunity to coronavirus disease 2019 (COVID-19)

• Published in: Infection Control & Hospital Epidemiology 2021-02, Vol.42 (2), p.205-207
• Main Authors: Henderson, David K, Haessler, Sarah D, Hayden, Mary K, Weber, David J, Babcock, Hilary, Malani, Anurag, Wright, Sharon B, Murthy, A Rekha, Guzman-Cottrill, Judith, Rock, Clare, Van Schooneveld, Trevor, Forde, Corey, Logan, Latania K
• Format: Article
• Language: English
• Subjects: Animals; Antibodies; Asymptomatic; Coronaviruses; COVID-19; COVID-19 - immunology; COVID-19 - prevention & control; COVID-19 Vaccines; Disease control; Disease Models, Animal; Disease prevention; Drug Development - trends; Humans; Immune response; Immunity, Cellular; Immunity, Humoral; Infections; Lymphocytes; Measles; Medical research; Pandemics; Plasma; Proteins; SARS-CoV-2 - immunology; Severe acute respiratory syndrome coronavirus 2; State of the Pandemic
• ISSN: 0899-823X; 1559-6834
• DOI: 10.1017/ice.2020.442

Many anecdotes describing the successful use of convalescent plasma have been reported, but only 1 controlled trial has been reported—it was underpowered and was terminated before statistical significance could be achieved.18 Other large, blinded controlled trials are underway.19 A recently posted preprint, which has not yet been peer reviewed, from the large, expanded access trial coordinated by the Mayo Clinic, identified reduced mortality associated with both the administration of higher antibody-titer plasma as well as with earlier administration of the plasma for hospitalized COVID-19 patients.20 More recently, investigators have demonstrated that antibodies directed against the SARS-COV-2 spike protein are neutralizing and correlate with protection against reinfection in a macaque model.21 Cellular immunity Several recent papers suggest that cellular immunity likely plays a key role in defense against COVID-19. [...]these 3 individuals who were known before the outbreak to have robust antinucleoprotein antibody responses and neutralizing antibodies were apparently protected from infection. A Centers for Disease Control and Prevention (CDC) website states clearly that they are not aware of any confirmed reports of COVID-19 reinfection occurring within 90 days of the primary infection.34 The absence of documented reinfections indirectly argues for at least short-term protective immunity in recovered individuals. In summary, although far from conclusive, the studies of natural, humoral, and cellular immunity, when considered in context with the findings from the animal rechallenge studies, provide substantial encouragement for the concept that recovery from COVID-19 is associated with a robust immune response that includes both humoral and cell-mediated responses.