St. Jude takes the lead on prevention and treatment of COVID-19 in vulnerable kids

During the COVID-19 pandemic, trying to control the spread of infection became an everyday aspect of life. Masks, hand sanitizer and social distancing were commonplace, with one major goal: to protect the most vulnerable groups from infection. Children with cancer are often left immunocompromised by their treatments, making them among the most at risk of infection from pathogens such as SARS-CoV-2.  

However, in a recent JAMA Network Open study, St. Jude researchers showed that even when immunocompromised pediatric patients experienced COVID-19, most were asymptomatic or had only mild disease. But having COVID-19 resulted in another problem: Most patients (87%) had their cancer treatments interrupted.

Interruptions in scheduled chemotherapy have previously been shown to impact patient outcomes, making it imperative for physicians to balance managing infections and the patient’s cancer. To provide insight into what should be the best practices in these situations, the researchers looked at patient records to conduct a retrospective analysis of patients treated for acute lymphoblastic leukemia (ALL) or lymphoblastic lymphoma (LLy) at St. Jude from 2020 to 2022. 

“I think the comforting thing for us was that severe disease was rare in our patients,” said first author Saman Hashmi, MD, St. Jude Departments of Global Pediatric Medicine and Oncology. “Only a small minority of patients, about 6%, had severe illness. We also did not see increased mortality from COVID-19 in our patient population during this period, which was reassuring. Despite severe disease, patients did recover and were then able to return to their scheduled chemotherapy.”

Chemotherapy can now continue during mild or asymptomatic COVID

During the pandemic, oncologists were cautious. If COVID was detected in a patient, chemotherapy was suspended until the infection resolved. As chemotherapy compromises the immune system, physicians feared severe infections would occur in these patients.  

“Withholding chemotherapy made sense when we did not know anything about COVID,” said corresponding author Hiroto Inaba, MD, PhD, St. Jude Department of Oncology member and Leukemia/Lymphoma Division interim director. “But our results suggest that if a patient has a mild or asymptomatic infection, we may continue with chemotherapy.”

Identifying potential severe infections, therefore, becomes critical. To that end, the researchers found multiple risk factors for severe disease:

• Older age
  
• Higher white blood cell counts at ALL/LLy diagnosis
  
• Lower absolute lymphocyte counts at COVID-19 diagnosis
  
• Abnormal chest imaging findings
  

“These findings told us that there is a subgroup of patients who are at higher risk of having severe COVID-19 and that we should watch this is the group of patients more carefully, perhaps with other serious viral illnesses in the future as well,” Hashmi said. 

Accounting for chemotherapy interruptions in the future

While physicians are worried about COVID-19’s impact during cancer treatment, interrupting chemotherapy is also a risk. Previous studies have shown that missed chemotherapy doses correlate with lower long-term cancer survival rates. It is unclear whether those poor outcomes will be reflected in patients whose treatment was delayed due to COVID-19. For now, physicians and researchers are closely following this cohort, paying special attention to what happens to this group as they age.

“Chemotherapy administration was affected for most patients, even those who were asymptomatic or had mild illness,” Hashmi said. “We don’t know what the effect of this will be on the long-term survival outcomes of patients with ALL/LLy. It will be important to account for this interruption and compare patients who developed COVID-19 during therapy for ALL/LLy with those who did not when we analyze future outcomes.” 

All future studies of cancer patients with interrupted treatment during the pandemic could be affected. Not taking the period into account may lead to incorrect findings or mask others. ALL is the most common childhood cancer, so a large number of patients may be able to statistically overcome that challenge. The effect can be more pronounced for cancers with fewer patients, where each COVID-19 patient may represent a larger percentage of the total population.

St. Jude infectious diseases doctors help guide the world

While chemotherapy was interrupted, the truly profound finding was how well COVID-19 prevention and treatment guideline implementation worked to prevent severe COVID disease.

“We protected patients because we identified and isolated cases very early, employing high-level infection control practices,” Inaba said. “We couldn’t stop the pandemic, but we screened all patients and medical staff. That led to comprehensive infection control and very accurate data we could use.”

Several experts from St. Jude, who designed the institution’s treatment guidelines, were recruited to join the Pediatric Infectious Diseases Society (PIDS) Pediatric COVID-19 Therapies Taskforce to develop national COVID-19 guidelines. PIDS sets standards for clinical guidance around managing childhood pathogens. The updated consensus statement was published recently in the Journal of the Pediatric Infectious Diseases Society. 

“Representatives of St. Jude infectious diseases and clinical pharmacy helped develop these guidelines, especially regarding this uniquely vulnerable population,” said co-corresponding author Josh Wolf, MBBS, PhD, of the St. Jude Department of Infectious Diseases. “These new national guidelines for prevention and treatment of COVID-19 in pediatric patients, including in immunocompromised children, are the first comprehensive pediatric guidelines in the post-vaccine era.”

The report is drafted by a multi-center collaboration of experts, including four from St. Jude. As a co-author on the JAMA Network Open study, Wolf summarized what these two publications show about the institution’s researchers: “These are great demonstrations that St. Jude is leading clinical science in the world of infectious diseases as well as pediatric cancer.”