Longevity of hybrid immunity against SARS-CoV-2 in adults vaccinated with an adenovirus-based COVID-19 vaccine

• Published in: BMC infectious diseases 2024-09, Vol.24 (1), p.959-8, Article 959
• Main Authors: Mvula, Memory, Mtonga, Fatima, Mandolo, Jonathan, Jowati, Chisomo, Kalirani, Alice, Chigamba, Precious, Lisimba, Edwin, Mitole, Ndaona, Chibwana, Marah G, Jambo, Kondwani C
• Format: Article
• Language: English
• Subjects: Adenoviridae - immunology; Adenoviruses; Adult; Adults; Aged; Antibodies; Antibodies, Neutralizing - blood; Antibodies, Neutralizing - immunology; Antibodies, Viral - blood; Antibodies, Viral - immunology; Antigens; Breakthrough infection; Cohort Studies; COVID-19; COVID-19 - immunology; COVID-19 - prevention & control; COVID-19 vaccines; COVID-19 Vaccines - administration & dosage; COVID-19 Vaccines - immunology; Cross Reactions - immunology; Female; Health aspects; Humans; Hybrid immunity; IgG antibody; Immune response; Immunity; Immunoassay; Immunoglobulin G; Immunoglobulin G - blood; Immunoglobulin G - immunology; Infection; Infections; Longevity; Longitudinal Studies; Male; Medical research; Medicine, Experimental; Middle Aged; SARS-CoV-2; SARS-CoV-2 - immunology; Severe acute respiratory syndrome coronavirus 2; Spike Glycoprotein, Coronavirus - immunology; Vaccination; Vaccines
• ISSN: 1471-2334; 1471-2334
• DOI: 10.1186/s12879-024-09891-z

Hybrid immunity provides better protection against COVID-19 than vaccination or prior natural infection alone. It induces high magnitude and broadly cross-reactive neutralising anti-Spike IgG antibodies. However, it is not clear how long these potent antibodies last, especially in the context of adenovirus-based COVID-19 vaccines. We conducted a longitudinal cohort study and enrolled 20 adults who had received an adenovirus-based COVID-19 vaccine before a laboratory-confirmed SARS-CoV-2 infection. We followed up the study participants for 390 days post the initial breakthrough infection. We assessed the longevity and cross-reactive breadth of serum antibodies against SARS-CoV-2 variants of concern (VOCs), including Omicron. The binding anti-Spike IgG antibodies remained within the reported putative levels for at least 360 days and were cross-neutralising against Beta, Gamma, Delta, and Omicron. During the follow up period, a median of one SARS-CoV-2 re-infection event was observed across the cohort, but none resulted in severe COVID-19. Moreover, the re-exposure events were associated with augmented anti-Spike and anti-RBD IgG antibody titres. This study confirms that hybrid immunity provides durable broadly cross-reactive antibody immunity against SARS-CoV-2 variants of concern for at least a year (360 days), and that it is further augment by SARS-CoV-2 re-exposure.