Why COVID Takes A Harsher Toll On Children With Cancer

Early in the pandemic, one bit of encouraging news was that children weren't as vulnerable to COVID-19 as adults.

But doctors who treat children with cancer had special concerns.

These kids have impaired white blood cells — the ones that fight infection. That can be a result of the cancer itself or of cancer treatments like chemotherapy. So when it comes to common respiratory infections like the flu, children with cancer tend to show more severe symptoms.

Would COVID also be more severe in this population?

To answer that question, doctors at St. Jude Children's Research Hospital collected reports of COVID cases among 1,500 cancer patients up to age 18, drawing from institutions in 45 countries. The data has been entered into a Global Registry of COVID-19 in Childhood Cancer created along with the International Society of Paediatric Oncology.

The study's findings are reported Thursday in The Lancet Oncology: "Global characteristics and outcomes of SARS-CoV-2 infection in children and adolescents with cancer."

Dr. Sheena Mukkada, an infectious disease specialist at St. Jude and one of the main authors of the study, spoke to NPR about how pediatric cancer patients have fared over the course of the pandemic. Her comments have been edited for length and clarity.

What did you think you would find when you began this study?

We were concerned because children with cancer do worse with respiratory viruses. So we always had fear that they were not going to do well.

Were your fears correct?

Of the kids with cancer, 20% had a severe critical infection with COVID. And death occurred in about 4% of all patients – considerably greater than the general pediatric population with COVID.

How do those rates of severe infection and death compare to the rates in the general population of kids?

We did not do a direct comparison to kids in the general pediatric population. But coming from the literature, severe disease [in that population] is between 1 and 6%. Death is even less than 1% in a lot of these studies.

Of the children whose deaths were reported in your study, what was the cause of death?

We specifically teased out the group that was due to COVID — that was 4%. The overall death rate [among the 1,500 children in the database] was more like 6% total.

And those additional deaths were due to...?

I'd be speculating. Some of it is related to cancer, some to delays in care – all kinds of factors.

Were the rates of severe disease and death among kids with cancer consistent around the world?

The outcomes of severe and worse [coronavirus] disease were more pronounced in low- and middle-income settings. It's a further illustration of a fact we already know: How interruptions in health service delivery and access to treatment in those countries affect outcomes. It's always sad to see that. It underscores why we have to equitable access to everything — coronavirus vaccines, supportive care.

And that lack of access to care isn't just a pandemic problem.

80% of children in high income countries will survive their cancer. In lower-income countries it's more like 10 to 20%.

I'm curious – have kids with cancer been impacted in other ways because of the pandemic?

We are seeing the disruption of supplies of blood products, other supportive care intervention. There was quite a good study in The Lancet earlier this year where that point was examined.

What advice do you have for families where a child has cancer during this pandemic?

If children with cancer are the age indicated for vaccines, they should get the vaccines. People around them should be vaccinated to prevent spread.

Any additional ways to protect kids with cancer from getting a COVID infection?

I can't say enough about the importance of hand-washing and wearing masks. Because caregivers and kids with cancer already were practicing better hygiene, that might have been blunting some of the impact of the pandemic.

How do kids with cancer respond to becoming infected?

For a lot of them it's annoying to have to be in isolation.

Is this study optimistic or pessimistic in its findings?

Most kids do well. 80% of the childhood cancer patients had an asymptomatic, mild or moderate course of COVID-19 disease. But I think the real message is that 20% of kids don't do well. We have to follow them more closely, decide if they need to receive therapy for COVID, agonize over what we give them.

Why agonize?

It's always a question of the risk of administering a medication versus the benefit. We are pediatricians, and we don't like giving children medication unless we think they will benefit from it.

Just before talking to you I was responding to an email about a patient who's infected, debating whether to give the child monoclonal antibody therapy or would the child do well without that therapy.

And you must also decide whether to interrupt cancer treatments if the patient contracts COVID.

The majority of patients with COVID are able to do quite well [with cancer treatment]. If a child has low white blood cell counts, we would hold the next cycle of chemotherapy while waiting for COVID to resolve. But we don't want to hold off forever.

The data for COVID is still too new and numbers in children still too low to make it clear who we treat and how we treat them. With our data, we hope to inform recommendations on which patient characteristics are associated with severe illness so that we don't interrupt cancer therapy for everyone. We don't want treatment interruptions to threaten cancer-related outcomes.

And now there's the delta variant to worry about.

I hate to leave on a note that's not so positive. But with delta, we are seeing more cases in the general pediatric population with symptoms they never really had in the first wave – respiratory symptoms that require hospitalization because they can't breathe well. We fear a little bit what's going to happen with the pediatric population that has cancer.

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