Results from a small study carried out at the Children’s Hospital of Philadelphia suggest that convalescent plasma from patients who have been infected with SARS-CoV-2 can be safely given to children with severe COVID-19 and may be effective at treating the infection.

While severe COVID-19 is rare in children, there are a small number of cases across the world and treatment options are limited. This small study, led by David Teachey, MD, Director of Clinical Research at the Center for Childhood Cancer Research at CHOP, indicate that convalescent plasma could be a good option for these children.

In the absence of approved and available treatments for SARS-CoV-2 infection, clinicians have been using a variety of off-label treatments, as well as plasma taken from the blood of patients who have recovered from the infection, to treat severe cases of COVID-19 since early in the year.

Plasma—the fluid left behind when blood cells are removed—is rich in antibodies and can theoretically help patients fight off the infection. There has been considerable debate about how effective it is at improving patient outcomes, but it has been approved by the FDA as an emergency treatment for the condition in adults. There is some evidence to suggest it might be effective, but the results of bigger studies are needed to prove this conclusively.

“Some children who contract this virus can develop very serious complications, so even with limited data in adults, we believed it was worth exploring the use of convalescent plasma as a possible treatment option,” said Teachey.

As reported in the journal Pediatric Blood and Cancer, Teachey and his colleagues gave convalescent plasma to four children aged 14-18 years who were admitted to hospital with severe COVID-19 and acute respiratory distress syndrome. Each patient received all the available plasma from their donor, which ranged from 200-220 ml.

The researchers observed no adverse events as a result of the infusions. They measured the level of antibodies the patients had in their system both before and after treatment. One of the patients had high levels to begin with and seemed to be recovering, but sadly died of cardiac complications 25 days after the infusion.

The other three patients had low initial antibody levels. After transfusion, they all had a boost in IgG, IgM, and IgA antibodies against the virus that lasted for 7-26 days. One patient of the three survivors has been discharged. The other two patients improved, but are still in hospital.

While the numbers in this study are too low to make any firm claims about efficacy, the patient that had the best response to treatment and was subsequently discharged from hospital was given donor plasma that had the highest level of antibodies. This fits with research in adults that has also suggested that plasma with a higher level of antibodies is a more effective treatment.

The FDA has also stipulated that donated plasma should be tested and labelled as having high or low levels of antibodies, although technically clinicians are able to give any donated plasma to their patients under the emergency use approval that came into force in August.

“We believe that convalescent plasma may provide the greatest benefit for patients who are early into their illness and have not yet generated endogenous antibodies,” commented Teachey.

“While the small sample size of our study does not allow us to draw any definitive conclusions, we believe this method is safe and future research should include randomized controlled trials to more definitively examine how effective convalescent plasma may be in treating children infected with COVID-19.