H1N1 Vaccine Working Well for Moms-to-Be

As pregnant women continue to line up to get the H1N1 vaccine, government tests released today show how well it can protect them, reports CBS News medical correspondent Dr. Jennifer Ashton.

Twenty one days after receiving a single dose of the vaccine, 92 percent of pregnant women had adequate immunity from H1N1.

"This should be reassuring news to women who have received the vaccine, and it is vital information for those pregnant women who have not been vaccinated," said Dr. Anthony Fauci of the National Institute of Allergy and Infectious Disease.

A single dose of the swine flu vaccine works well for almost all pregnant women, but young children will still need two doses for best results, federal health officials said.

Twenty-one days after receiving a single 15-microgram dose of the vaccine, 92 percent of pregnant women showed a robust immune response, Dr. Fauci reported.

A larger, 30-microgram dose produced a strong response in 96 percent of pregnant women, said Fauci, director of the National Institute of Allergy and Infectious Disease.

"This should be reassuring news to those women who have received the vaccine," Fauci said.

CBSNews.com Special Report: H1N1

While a single dose is recommended for healthy adults and pregnant women, officials have said younger children will need two doses.

That has been confirmed by continuing studies, Fauci said.

He said among children aged 6 months to 35 months just one in four had a strong immune response after 21 days. For those 3 years to 9 years old it was 55 percent. There was a sharp improvement after a second dose, he said, raising the fully protected rate to 100 percent in those 6 months to 35 months and 94 percent in those aged 3 years to 9 years.

60 Minutes: An Inside Look at H1N1 Vaccine Production
Flu.gov: Where To Get Your Flu Shots
CDC: Learn More About H1N1
CDC: What To Do If You Get Sick
CBSNews.com: H1N1 Parents' Guide

Giving the larger 30 microgram dose gave no added benefit, Fauci said.

Also at the briefing at the Department of Health and Human Services:

Dr. Anne Schuchat, director of the National Center for Immunization and Respiratory Disease at the Centers for Disease Control and Prevention, said the flu is currently widespread in 48 states and hospitalizations and deaths continue to increase.

She said 30 million doses of the vaccine are available as of Monday. There will be continued challenges, she said, but the supply is expected to catch up with demand.

Dr. Bruce Gellin, director of the National Vaccine Program Office, reported that a program to monitor any side effects is in place with a new safety advisory working group meeting Monday.