Agence France-PresseJuly 7, 2021 14:42:27 IST
How effective are Covid vaccines if HIV, cancer or a recent transplant endanger the immune system?
Researchers are working to find out how they can best be protected because they have little information – and fear that some of these patients may be particularly susceptible to the virus.
In one of the largest research projects to date, dozens of French hospitals have launched a two-year study involving around 10,000 people to help shed light on how these conditions suffer from coronavirus immunization.
“The goal is to find out how we can best protect these patients,” study manager Odile Launay told AFP.
Authorities, such as the U.S. Centers for Disease Control and Prevention, say people with a weakened immune system can get the vaccine, but stress that there is still little information about safety.
“If you have an illness or are taking medications that weaken your immune system, you may not be fully protected even if you are fully vaccinated,” the CDC adds and urges people to continue to take precautions and contact their doctor.
People’s immune systems can be suppressed by a disease – or by treatments taken to treat other diseases – and this can mean that their bodies have difficulty producing antibodies that vaccines are supposed to trigger.
Situations where this may be the case include diabetes, obesity, cancer, organ and bone marrow transplants, chronic severe renal failure, HIV or multiple sclerosis.
In the case of a transplant, the patient’s immune response is deliberately suppressed to prevent his body from attacking the new organ.
Another study, published in the French New England Journal of Medicine, looked at 100 transplant patients and found that their immune response to vaccines was inadequate after two doses.
The researchers recommended three doses for patients, which is now the rule in France.
The new study, which involves 30 hospitals and has registered participants since March, is aimed at 8,650 participants with a weakened immune system and a control group of 1,850 people.
Participants are bled to measure the presence of antibodies at the time of vaccination and then again one month, six months, one year, and then two years after the last dose.
“The data allows us to tailor our vaccine recommendations to specific patient groups,” Launay said.
For example, health authorities may decide to reduce the waiting time between the first dose and two or three booster vaccinations that would likely follow in immunocompromised patients.
And in cases where vaccines did not work, doctors opted for other strategies, such as vaccinating the patient’s family and caregivers and maintaining social distance.
If the failure of the vaccine results in Covid-19 infection, the researchers also sequenced the virus.
This can pick up on whether the disease is causing an existing variant – or even pick up new mutations.
Although Covid-19 virus typically infects individuals for about 10 days before being neutralized by the body, some studies have shown that certain patients, especially those with a weakened immune system, can carry it for several weeks or longer.
This increases the chance of the virus mutating, which can lead to new variants.
In the UK, a similar study was launched in March to monitor the response of 5,000 immunocompromised patients to Covid-19 vaccinations.
“We urgently need to understand whether groups of patients with chronic diseases such as cancer, inflammatory arthritis, and kidney and liver disease are likely to be well protected with current COVID-19 vaccines,” time lead researcher Iain McInnes of the University of Glasgow said.