COVID-19 SCIENCE | Modified T cells may help those on immunosuppressants; ECMO machines improve survival

A summary of some recent studies on Covid-19. They include research that warrants further study to corroborate the findings and which are yet to be certified by peer review.

Modified T cells not curbed by immunosuppressants

A technique for modifying virus-attacking T cells might help defend against Covid-19 in patients who must take drugs that suppress the immune system, preliminary findings suggest.

Transplant patients, for example, are particularly vulnerable because of the medicines they take to prevent rejection of the new organ. German researchers have found that Covid-19 survivors' T cells, which have learnt to recognise and attack the virus, can be genetically modified to make them resistant to tacrolimus, a immunosuppressive drug that is widely used to prevent rejection after transplant.

In test-tube experiments, treatment with tacrolimus did not inhibit the ability of the modified T cells to recognise and attack the coronavirus, according to a report published on Saturday in Molecular Therapy: Methods and Clinical Development.

The researchers are planning a trial in which the tacrolimus-resistant T cells will be infused into human volunteers. “With this strategy, virus-specific T cells can fight against SARS-CoV-2 despite ongoing immunosuppression in the patient,” said Michael Schmuck-Henneresse of Charite-Universitatsmedizin Berlin and the Berlin Institute of Health.

“Our approach to make T cells resistant to tacrolimus can theoretically be transferred to different immunosuppressants and (viruses) by adapting the manufacturing protocol and thus has great potential for a wide range of applications,” he said.

Covid-19 survival better with ECMO than without

Lack of access to machines that add oxygen to blood while letting the heart and lungs rest — a treatment known as ECMO — has contributed to US deaths during the pandemic, according to new data.

At Vanderbilt University Medical Center in Nashville, researchers tracked 90 critically ill Covid-19 patients who were medically eligible for extra corporeal membrane oxygenation, or ECMO, from January to August 2021. Half were under the age of 40 and most were otherwise healthy. Overall, 39% received ECMO, including some who had to be transferred to another hospital to get access to the treatment. For those for whom ECMO could not be arranged — for lack of equipment, intensive care beds, or nurses — 89% died, roughly twice the 43% mortality rate in the ECMO-treated group, the researchers reported on Thursday in the American Journal of Respiratory and Critical Care Medicine.

With ECMO, “every patient needs their own nurse, which is very difficult ... when you are already managing shortages of nursing staff,” said Dr Jonathan Dale Casey. Providing ECMO may mean not having room for other Covid-19 patients or cancelling urgent procedures for non-Covid-19 patients, he added.

Because many ECMO-treated patients die given the severity of their condition, “I think many doctors and hospitals wondered during the pandemic whether ECMO was worth the intensive resource investment,” Casey said. “I hope our article answers that question. Our goal with writing it was to make the public aware that people were not getting this life-saving resource because of resource limitations, and to encourage investment in ECMO infrastructure.”

Pandemic-linked caregiver deaths nearly double since April

More than 5.2-million children worldwide have lost a parent or caregiver to Covid-19, researchers say.

They estimate based on mathematical models that from March 1, 2020 through to October 31, 2021, at least 3,367,000 children suffered the loss of a parent as a result of the pandemic. An additional 1,833,300 children lost a grandparent or other adult caregiver, they reported on Thursday in The Lancet Child & Adolescent Health. Those numbers are nearly twice as high as the estimates they reported after the first 14 months of the pandemic up to April 2021, they noted.

The number of children in the 20 countries studied who lost a parent ranged from 2,400 in Germany to more than 1.9-million in India. In the US, 149,300 children lost a mother or father, the authors estimate. In Peru and SA, 8 and 7 children, respectively, out of every 1,000 lost a parent. In all countries, children were more likely to have lost a father than a mother.

“Real-time updated data suggests the true totals reached 6.7-million children as of January 2022,” study leader Dr Juliette Unwin of Imperial College London said in a statement. “The pandemic is still raging worldwide, which means Covid-19 related orphanhood will also continue to surge.”

Reuters