Flu Vaccination Timing Could Produce Better Response in Pediatric Patients with Acute Lymphoblastic Leukemia

Pediatric patients with acute lymphoblastic leukemia showed better response to the flu vaccine if they received it at a certain point during chemotherapy.

Administering the flu vaccine during the induction stage of chemotherapy in pediatric patients with acute lymphoblastic leukemia (ALL) could result in a better response to the vaccine, research from the Children’s Hospital of Philadelphia suggests.

The study, published in the November 2013 edition of Influenza and Other Respiratory Viruses, analyzed flu vaccine response in pediatric participants with ALL, sarcoma, or brain tumors. Researchers administered an inactivated influenza vaccine to participants, who were split into an ALL cohort or a solid tumor cohort, which included the participants with sarcoma or brain tumors.

Researchers collected laboratory study data and clinical data on the day of vaccination, and then at 2 month, 4 month, and 1-year points after the vaccinations occurred.

A stratified analysis examining the total affect of chemotherapy on vaccination response in ALL determined that vaccination during the induction stage of chemotherapy led to better vaccine responses than vaccination during the postinduction or maintenance phases of chemotherapy.

An analysis of participants’ B cells, including the total cells producing a specific immune antibody and those producing influenza-specific antibodies, revealed differences in cell counts associated with progression through chemotherapy.

Researchers analyzed ALL patients’ T-cell function and counts as well, noting that other immunologic variables can affect vaccine response. They found no significant difference in T-cell proliferation after introducing a viral agent in any of the cohorts. In addition, the researchers detected no clear signs of quantitative T-cell recovery in any of the cohorts.

“These data could be used to identify patients unlikely to respond to the vaccine who could be provided alternative types of protection such as oseltamivir,” the researchers noted. “Identification of a biomarker could be useful in stratifying patients for vaccinations or alternative approaches.”

In addition, researchers did not detect a statistically significant difference in vaccine response between patients with ALL, sarcomas, or brain tumors during their initial analysis, generalized estimating equations revealed greater response for H1N1 in participants with sarcomas or brain tumors.

An analysis of those participants’ B cells revealed no statistically significant differences between participants who were vaccinated when they received less than 1 month of chemotherapy, participants who had received between 1 and 3 months of chemotherapy, and patients who received more than 3 months of chemotherapy. There were no significant differences in T-cell responses in solid tumor patients, the authors noted.

Patients were immunized as the vaccine became available, rather than according to their progression through chemotherapy, the researchers noted. The most recent guidelines for administering influenza vaccinations to pediatric oncology patients recommend beginning vaccinations during maintenance or intermittent chemotherapy.

“Optimizing vaccination protocols to improve protection from this common yet preventable infection could lead to fewer/shorter hospital admissions and a[sic] lower in hospital transmission rates,” the authors wrote.