- Evolution of the Covid virus is likely to arise in patients with weakened immune systems.
- Cases around the world indicate that immunocompromised patients with Covid can have prolonged infections.
- A booster dose will become available in South Africa for certain patients with compromised immunity as of 1 December 2021.
For the past few months, scientists and health experts have advised that people with immunocompromised conditions (weakened immune system) should be closely monitored for persistent Covid-19 infections.
This is because evidence suggests that this group is not only at risk for severe Covid-19, but that they can also have prolonged infection and be contagious for much longer than average. As a result, this may provide the time and the evolution for new variants to emerge.
“That is something that the scientific community knows quite well since the emergence of the first variant,” said Professor Tulio de Oliveira, director of the KwaZulu-Natal Research Innovation and Sequencing Platform (KRISP).
De Oliveira was speaking at a briefing on Thursday, where he and his colleagues announced the discovery of a new variant, Omicron (B1.1.529), that has a combination of mutations that may cause the virus to evade immunity or transmit more quickly through the population.
UK patient with blood cancer
De Oliveira drew attention to the case of an immunocompromised patient in the UK infected with the then-dominant Alpha variant.
The patient was a man in his 70s who had been diagnosed with lymphoma in 2012. He was hospitalised with Covid pneumonia.
“He hadn’t been able to shake his illness since testing positive for SARS-CoV-2 more than a month earlier,” researchers wrote in JAMA Network.
The patient, who later succumbed to his illness, continued to test positive for the virus with a high viral load.
“This, along with his worsening illness, indicated that he was battling an ongoing infection with live, replicating virus for more than 100 days,” the authors noted.
His blood cancer, along with the treatment he received for it, had erased his B and T cells, which are important arms of the immune response and which left him “severely immunocompromised”, they said.
Immunodeficiency can be due to genetic defects that can be inherited, as the US Centers for Disease Control and Prevention (CDC) explains. But prolonged use of certain medications can lead to secondary or acquired immunodeficiency, it added.
This means that it makes it harder for an individual’s body to fight off infections or cancer.
Included are people with immune system disorders, patients with solid organ transplant patients, cancer patients receiving chemotherapy or radiation, people with blood cancers who have had CAR T-cell therapy, and people living with HIV, not on antiretroviral treatment (ART).
South Africa has the biggest HIV epidemic in the world, with 7.7 million people – 20% of the population – HIV-positive, while CANSA data indicates that 115 000 South Africans are diagnosed with cancer each year.
While 90% of people living with HIV are aware of their status, only 70% are on treatment.
Virus variants are, therefore, likely to spring from these patients, especially if they are not sufficiently protected by vaccination.
HIV ARTs critical
De Oliveira cautioned, however, that “HIV is not the problem”, and that people with HIV who are on antiretroviral therapy (ART) will respond very well to a Covid infection.
“And that’s the importance of HIV diagnosis and therapy,” he said.
Not possible to pinpoint source of variants
De Oliveira said: “So what we know in the scientific community is [that] ... immune-suppressed individuals are driving the evolution of the virus because they cannot clear the virus.”
While he said these types of cases were seen in dozens of countries around the world, and that they could play a potential role in the emergence of new variants, he added that it was not possible to pinpoint exactly what gave the virus the opportunity to mutate.
Other experts, for example, have long warned that unvaccinated individuals also pose a threat and give the virus more opportunities to multiply and become better and fitter.
Recommendations for booster dose
In some countries, including South Africa, there have been recommendations for a third dose of the Pfizer-BioNTech vaccine and a second dose of the Johnson & Johnson vaccine to be given to certain immunocompromised people to ensure they have sufficient protection against severe Covid.
In October 2021, health minister Joe Phaahla announced that the Ministerial Advisory Committee (MAC) on Covid-19 Vaccines has advised that additional doses be given to individuals with compromised immunity.
Acting director-general (DG) of the health department, Dr Nicholas Crisp, said that as of 1 December 2021, certain immunocompromised individuals will be eligible to receive an additional vaccine dose as part of their primary Covid vaccine schedule to enhance their immune protection.
Registration for the additional dose can be done on the EVDS Registration Portal, but the dose must be prescribed by a doctor or nurse prescriber who will have to complete a referral form.