According to scientists, the virus mutated about 50 times during a certain period. They caution that individuals with weakened immune systems are ideal hosts for deadly new strains of the disease. It is noted that while there have been several cases of patients carrying the virus for extended periods, a 72-year-old man is believed to have had the longest-lasting infection.
Healthy patients usually clear the virus within days to weeks, but those with compromised immunity can develop persistent infections due to prolonged viral replication and evolution. They speculate that the Omicron variant originated in an immunocompromised individual, emphasizing the need for vigilant monitoring of such patients. These findings will be presented at the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) global conference in Barcelona next week.
The patient had undergone stem cell transplantation treatment, rendering him immunocompromised. His condition was further complicated by the development of post-transplant lymphoma, for which he was receiving a targeted cancer medication that depletes all available B-cells, including those responsible for producing Covid antibodies. Despite receiving multiple Covid vaccinations, the elderly man showed no measurable antibody response upon hospital admission.
Although given additional treatments, including anti-SARS-CoV-2 directed antibodies and anti-inflammatory medication, he showed no clinical response. This prolonged infection led to the emergence of a new, immune-evading variant of the virus due to its extensive evolution within a host. Tragically, the elderly man eventually succumbed to a relapse of his blood condition.
Over his one year and eight months with the virus, the man’s infection led to prolonged isolation and the use of protective gear, greatly reducing his quality of life in his final days. Dr. Magda Vergouwe, lead author of the study, underlined the importance of tracking infections in vulnerable patients, warning of the potential public health threat of developing resistant mutations. She also stressed the need for a balance between tracking dangerous new variants and providing humane, supportive care to severely ill patients.
Possible solutions suggested by the researchers include increased awareness of potential risks, early accessible testing of known contacts of the patients, and genomic surveillance of the virus to assess the public health threat in collaboration with public health professionals. Dr. Vergouwe added that though there’s an increased risk of developing novel variants in immunocompromised patients, not every variant that develops will be of public concern. Factors in the population surrounding the patient, including the prevalence of B- and T-cell-related immunity, also influence the development of a variant of concern.
Dr. Vergouwe mentioned that prolonged infections in immunocompromised patients are much more common compared to the general community. The team’s further work includes describing a cohort of prolonged infections in immunocompromised patients from their hospital, with infection durations varying between one month and two years.
