Should patients with primary immunodeficiencies fear COVID-19 more than the general population?

Primary immunodeficiency (PID) is a congenital dysfunction (incorrect or completely missing function in a certain area) of the immune system caused by a mutation that leads to a defect in the production of proteins involved in immune processes. The severity of the disease depends on which part of the immune system is damaged. One of the risks for individuals with PID is vaccination with live vaccines.

PID and COVID-19

Almost everyone associates immune damage with an increased risk of diseases. However, scientists agree that the new coronavirus is somewhat peculiar - for example, young children, who also do not have a fully developed immune system, generally handle SARS-CoV-2 infection without complications and with a mild course. The good news is that international professional societies for primary immunodeficiency are monitoring their patients and the occurrence of this new coronavirus among them. The data collected so far speak of 15 patients with PID and COVID-19, with only 1 of 6 patients with an antibody deficiency having a severe course of the disease.

Are all patients with immunodeficiency at risk from COVID-19?

It is crucial for PID patients to know which part of their immune system is impaired. In the case of a viral infection, the following components are involved:

• Day 0-5: Local reaction (nasal mucosa) slows down virus replication (primarily interferons).
• Day 5-7: Activation and proliferation of defensive T lymphocytes, which produce cytokines (substances that spread information about infection and support immune responses, including fever), and subsequently attack the virus.
• Day 7-9: Antibody production.

The vulnerability varies depending on the type of immune system disorder the individual faces:

• Patients with antibody deficiencies: No increased risk compared to the general population is expected unless they also suffer from severe lung disease.
• Patients with a significant T lymphocyte deficiency: It is recommended to use all available methods of disease prevention because T lymphocytes are crucial for the body to eliminate the virus.
• Patients with phagocytosis disorders: The risk here is not posed by the virus itself (the body should be able to eliminate it comparably to a healthy individual) but by a bacterial superinfection that can join the weakened mucous membranes.

Therapy perspectives and drugs for PID during the pandemic

In the context of the COVID-19 pandemic, patients with various chronic diseases sometimes fear a shortage of specific drugs on the market, which could disrupt their current therapy. Individuals with PID who use immunoglobulins derived from the blood of healthy donors may also feel uncertain. Administering convalescent plasma is one of the promising modalities for COVID-19 therapy; however, this plasma will likely be sourced from patients who have already recovered from the disease rather than from existing donors. Therefore, it is not expected that the production of COVID-19 therapeutics will disrupt the manufacture of drugs for PID patients.

Vaccination perspectives

According to reports from professional sources, testing of the COVID-19 vaccine on healthy volunteers has already begun. None of the tested vaccines are live viral vaccines; they are combinations of viral subunits or protein components. However, it should be noted that the evaluation of vaccine safety and effectiveness will take relatively long.

Thus, the foundation of infection prevention remains adherence to social isolation principles, increased hand hygiene, wearing a respirator (protects the wearer from the disease), or a mask (protects others).

(mir)

Source: Immune Deficiency Foundation. COVID-19. Available at: https://primaryimmune.org/coronavirus