SARS-CoV-2 Vaccination in Patients with Primary and Secondary Immunodeficiency
November 8, 2022
A recent study, conducted in the UK, aimed to understand the risks associated with COVID-19 vaccination, monoclonal antibodies, and antiviral therapies in patients with primary and secondary immunodeficiency. Since people with immunodeficiency often experience impaired vaccine responses, investigating real-world vaccine efficacy in this group of patients is essential, especially since they are considered at-risk for severe COVID-19.
Researchers compared two groups of patients: the first group included patients infected with SARS-CoV-2 before vaccines became available, and the second group included patients who were infected after SARS-CoV-2 vaccines were widely distributed. In this second group, participants received an average of 2.73 vaccines at the time of infection.
Hospitalization rates for patients with primary immunodeficiency who had access to vaccines were 17.9%, compared to 53.3% for the unvaccinated group. Similarly, mortality rates improved in the second group (3.4%) compared to 20% in the group of unvaccinated patients.
Patients with secondary immunodeficiency also showed improvements. In the group that had access to vaccines, researchers observed an 18.4% hospitalization rate compared to 75.8% amongst unvaccinated patients. Similarly, mortality improved from 33.3% to 7.89%.
As vaccines became available, COVID-19 treatments also improved. To determine the effectiveness of COVID-19 vaccination, excluding other factors, researchers compared the unvaccinated group with people who were vaccinated but didn’t receive any pharmacological treatment upon infection. Once again, hospitalization and mortality rates improved.
Researchers also considered the differences between SARS-CoV-2 variants, specifically Omicron, which is believed to be more transmissible but causes less severe symptoms. They compared patients from the second group who had access to vaccines, who were infected with Omicron, to those infected with other variants. They observed lower hospitalization rates for patients infected with Omicron (41.5% vs. 9.9%, respectively) and lower mortality (9.8% vs. 2.7%, respectively). This could be due to boosters being readily available during the Omicron wave compared to periods where other variants were prevalent.
Overall, researchers observed improvements in COVID-19 outcomes in patients with immunodeficiency. They suggest that these improvements are most likely caused by several factors alongside vaccination, including therapeutics, the emergence of potentially less virulent SARS-CoV-2 variants, and non-pharmacological interventions, such as restricting social interactions.