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Do vitamins A and D help the flu vaccine work better? It depends.

October 8, 2019

(L to R) Dr. Julia Hurwitz, Dr. Nehali Patel

(L to R) Dr. Julia Hurwitz, Dr. Nehali Patel

Vitamins A and D influence the immune system. Researchers suspected these vitamins might affect how well children respond to the flu vaccine. But earlier studies by other scientists showed mixed results.

A new St. Jude study may have the answer. Baseline vitamin levels are rarely studied in flu vaccine research. But scientists found that baseline vitamin A and D levels were linked to immune responses to the vaccine.

A clinical trial studied the flu vaccine and vitamin supplements in children 2–8 years old. Children got two doses of the vaccine either with a vitamin A and D supplement or a placebo.

“Baseline vitamin A and D levels each influenced the flu vaccine-induced immune response and the effect of high-dose vitamin supplements,” said Julia L. Hurwitz, PhD, of the St. Jude Department of Infectious Diseases.

A report on this work appeared in Viruses.

St. Jude Children's Research Hospital

St. Jude Children's Research Hospital is leading the way the world understands, treats and cures childhood cancer, sickle cell disease, and other life-threatening disorders. It is the only National Cancer Institute-designated Comprehensive Cancer Center devoted solely to children. Treatments developed at St. Jude have helped push the overall childhood cancer survival rate from 20% to 80% since the hospital opened more than 60 years ago. St. Jude shares the breakthroughs it makes to help doctors and researchers at local hospitals and cancer centers around the world improve the quality of treatment and care for even more children. To learn more, visit, read St. Jude Progress, a digital magazine, and follow St. Jude on social media at @stjuderesearch.