Jenny and Allan Landstreet reminded themselves not to panic.
Their 2-year-old son, listless and feverish, had just been diagnosed with influenza, also called flu. But the couple’s worries swiftly turned to their 4-year-old daughter, Mabry, who was receiving treatment at St. Jude Children’s Research Hospital for acute lymphoblastic leukemia (ALL). Because Mabry’s immune system was weakened from chemotherapy, flu might pose dangerous complications.
Common-sense measures, such as disinfecting household surfaces, washing hands frequently and keeping Mabry apart from her brother, helped allay the Landstreets’ anxiety. Mabry’s St. Jude doctors also prescribed an antiviral medicine to nip the illness in the bud. The strategy worked: Even though Mabry got flu, it took a fairly mild course, triggering only a low fever, runny nose and postponement of scheduled chemotherapy treatments.
“We were lucky,” Jenny says, “because an illness that our body could fight could have been so much worse for Mabry.”
Vitamins and infection
Mabry’s experience reinforced the importance of St. Jude research focused on making the flu vaccine more effective.
According to the U.S. Centers for Disease Control and Prevention (CDC), influenza has killed as many as 49,000 Americans and about a half-million children worldwide per year. The CDC considers vaccination to be the best step to prevent flu. But during the 2015–16 flu season, the CDC reported that the flu vaccine was only 60 percent effective, underscoring the need to improve the vaccine’s potency.
In a paper published in the journal Clinical Vaccine Immunology, a team led by Julia Hurwitz, PhD, of the St. Jude Infectious Diseases department, showed that vitamins A and D help boost the body’s response to the flu vaccine. Now, clinical trials at St. Jude are exploring whether a simple supplement of those vitamins, given at the time of vaccination, can protect children from catching flu.
A and D to the rescue
Vitamins A and D are present in foods, and vitamin D is also made in the body in response to sun exposure. But changes in the U.S. diet are chipping away at the baseline levels of these nutrients. Hurwitz discovered this during previous research that tested vitamin levels in children and adults from Memphis.
“We found nutritional deficits, vitamins A and D among them,” she explains. “Based on those findings, we began to question why the influenza virus vaccines were not working well, particularly in children in this city.”
Hurwitz has long been interested in the activity of B cells, the white blood cells that circulate through our bodies and make antibodies to protect us from germs such as the influenza virus. If a person lacks healthy levels of vitamins, their B cells may not produce the antibodies our bodies require.
Hurwitz and her colleagues found that a shortage of vitamin A decreased the body’s immune response to vaccines against respiratory viruses. So the scientists set out to see whether deficiencies in both vitamins A and D would worsen matters.
That’s what happened.
In the lab, Hurwitz also found that giving vitamins A and D restored immune responses to the flu vaccine.
First-ever trial in humans
As a result of that research, St. Jude has launched a clinical study to examine immune responses to the flu vaccine in relation to vitamin levels and vitamin supplements.
The St. Jude FLUVIT trial is designed to find out whether children produce normal immune responses if they receive a vitamin supplement when they receive the flu vaccine.
Led by Nehali Patel, MD, of the St. Jude Infectious Diseases department, the study is enrolling 80 healthy children ages 2 to 8 over two to three flu seasons. Researchers first measure the vitamin levels present in the children’s blood. Half of the children then consume a chewable gummy vitamin A and D supplement when receiving the flu vaccine. The other half receive a placebo supplement, or “dummy” gummy, at the time of vaccination.
Subsequent blood tests measure vitamin A and D levels in the children’s blood. Scientists also check antibody responses against flu.
Parents keep food diaries to track the children’s diets. And the parents’ education levels and other socioeconomic factors are logged to find out whether these affect the children’s nutritional status. By 2018, Hurwitz, Patel and their colleagues hope to show that when vitamins A and D are provided to children at the time of flu vaccination, there is an improvement in vaccine potency.
“People may not be willing or able to take vitamins on a daily basis, but this is just a one-time vitamin intervention that could be given when you get the flu vaccine to help improve response,” Patel says. “So it’s actually a very practical solution.”