Higher doses of H1N1 vaccine being tested on pregnant women

The National Institute of Health (NIH) on Oct. 8 began the first clinical trials to test the safety and effectiveness of higher doses of the 2009 H1N1 influenza vaccine for pregnant women.

Additional tests begin this week to test the effectiveness of higher doses of the vaccine in HIV-infected children and young people.

The tests are based on the fact that pregnant women and people with HIV have a poor immune response to the normal dose of the seasonal flu vaccine, which is 15 micrograms, according to Anthony S. Fauci, M.D., director of the National Institute of Allergy and Infectious Diseases (NIAID).

“Moreover, children, young people and pregnant women are at higher risk for more severe illness from the 2009 H1N1 influenza virus than other groups,” Fauci said.

Therefore, the trials are testing the effects of 30 micrograms, according to an Oct. 9, 2009 NIH press release.

The vaccine, manufactured by Novartis Vaccines and Diagnostics, contains inactivated 2009 H1N1 influenza virus, so it is impossible to become infected with the virus by receiving the vaccine.

And the vaccine does not contain adjuvant, a substance added to some vaccines to improve the body’s response to vaccine.

Two studies

One trial will study 130 HIV-infected pregnant women, 18-39 years old, who are in their second or third trimester (14 to 34 weeks) of pregnancy.

The other trial will study 140 children and young people, 4 to 24 years old, who were infected with HIV at birth.

Thirty-five sites and eight subsites across the United States and Puerto Rico are eligible to conduct the trials.

Each volunteer will receive two 30-microgram doses of 2009 H1N1 influenza vaccine 21 days apart.

Safety data will be collected and monitored closely by the study investigators and an independent safety monitoring committee.

Monitoring newborns

The strength and longevity of the immune response elicited by the vaccine will be gauged in several ways.

The study team will take blood samples from the pregnant women after each dose – and three and six months after delivery – to measure the concentration of antibodies against 2009 H1N1 influenza virus the women produce, and how strong that antibody response remains over time.

After the women give birth, study staff will sample umbilical cord blood to measure the concentration of maternal antibodies against the H1N1 virus that were transferred to the infants through the placenta.

The study team also will collect small blood samples from the infants at 3 and 6 months of age, to measure their level of maternally-derived antibody protection from the virus over time.

The infants will not receive vaccine.

In children and young people, the strength and longevity of the immune response will be gauged by testing blood samples taken 21 days after the first dose, 10 days after the second dose, and six months after entering the study.

The International Maternal Pediatric Adolescent AIDS Clinical Trials Group is conducting the studies on children, which are sponsored and funded by the National Institute of Allergy and Infectious Diseases (NIAID) and the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), both part of the National Institutes of Health.

Posted Oct. 11, 2009

Related link: CDC reports 76 children have died after being infected with H1N1

http://news.yahoo.com/s/ap/20091010/ap_on_he_me/us_med_swine_flu_8

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Other resources

Visit www.flu.gov for one-stop access to U.S. government information on avian and H1N1 influenza and www.aids.gov for information about HIV/AIDS.