The University of Florida Center for HIV/AIDS Research is taking part in national clinical trials of the 2009 H1N1 influenza vaccine among children, youth and pregnant women who are infected with HIV.
The trials’ aim is to determine how well higher-than-usual doses of the vaccine trigger a protective immune response in the study populations. The trials will help clarify whether candidates need one or two doses, and allow continued evaluation of the vaccine’s safety. The strength of the response — and how long it lasts — will be evaluated.
Clinical trials have shown that a 15-microgram dose of the 2009 H1N1 vaccine protects healthy adults and older children. But children, youth and pregnant women who have HIV might not be as well protected by the same doses. Trial participants will receive two 30-microgram doses of vaccine by injection 21 days apart.
“In the immune-suppressed population there is always a concern that they may not be able to respond to the vaccine,” said professor Mobeen Rathore, M.D., director of the UF Center for HIV/AIDS Research — also known as UF CARES — who is leading the UF trials. “We give the vaccine realizing that it may or may not work — provided it is safe.”
The FDA-approved study vaccine contains inactivated 2009 H1N1 influenza virus and so cannot cause infection.
HIV compromises the immune system, making people more vulnerable to attack from disease-causing agents. Pregnant women who have HIV are at increased risk because of their pregnancy in addition to a suppressed immune system. The 2009 H1N1 influenza appears to cause a much higher mortality rate among pregnant women than among others. But even with the “regular” seasonal flu, pregnant women are at increased risk of sickness and death, including fetal death.
Children generally are at higher risk from H1N1 influenza because their immune systems are not as well-developed as those of older persons. In addition, adults have some level of protection against the 2009 H1N1 flu virus because of previous exposure to similar flu viruses, something young children generally lack.
One trial will enroll 130 pregnant women age 18 to 39 who are in their second or third trimester. Women will take part in the study until six months after delivering their babies. Their newborns will be studied during the first six months of life.
The other trial will involve 140 children and youth age 4 to 24 who were infected with HIV from birth. They will be followed for seven months from enrollment.
Blood samples from subjects will be analyzed to determine the level of antibodies produced against the 2009 H1N1 flu virus and how those levels change over time. Newborns will be tested to see how much of maternal antibodies were transferred to them from their mothers.
Participants at UF’s study site will come from existing patient groups with which UF CARES works. The organization is the largest comprehensive HIV education program in North/Central Florida, and performs NIH-funded HIV/AIDS research in infants, children, adolescents and women — including pregnant women. The program is staffed by a multidisciplinary team of researchers, physicians and other health professionals.
The vaccine trials are being conducted at 35 sites and eight sub-sites around the United States and Puerto Rico that are members of the International Maternal Pediatric Adolescent AIDS Clinical Trials Group. The National Institute of Allergy and Infectious Diseases and the Eunice Kennedy Shriver National Institute of Child Health and Human Development, both part of the National Institutes of Health, are sponsoring and funding the trials.
But Rathore, who is trained as a vaccinologist, isn’t just concerned about people who are in the trial population.
“Whether one is participating in the study or not, I think it’s important that everybody get the H1N1 vaccine to protect ourselves,” he said.