WEDNESDAY, July 29, 2009 (HealthDay News) -- As U.S. officials meet Wednesday to decide who should get priority for potentially scarce H1N1 swine flu shots this fall, the danger the virus poses to pregnant women should vault that group to the top of the list, experts say.
A panel convened by the U.S. Centers for Disease Control and Prevention is expected to release its recommendations on vaccine distribution priorities later on Wednesday. Beyond that, the first trials of a vaccine against the new H1N1 swine flu are set to begin soon, and experts hope for the first batch of viable shots to be distributed by October, if all goes well.
"The panel will get an update on the H1N1 in the United States," said CDC spokesman Tom Skinner. "They will get an update on where things stand with the development of a vaccine against novel H1N1 and an update on the steps being taken to plan for a potential vaccination campaign in the fall."
But a study published in the July 29 issue of The Lancet should weigh heavily on the CDC panel's decision. It confirmed that pregnant women are at especially high risk of complications from the new flu strain.
"Pregnant women who have been infected with H1N1 influenza have had a higher rate of hospitalization, about a fourfold increase compared with the general population and a higher proportion than expected of the deaths were among pregnant women," noted study author Dr. Denise J. Jamieson, a CDC medical officer.
Based on those findings, "I would expect that pregnant women will continue to be a high-priority group for vaccination," Jamieson said, so pregnant women who get the H1N1 flu should receive prompt treatment with antiviral medications.
In fact, the first American to die from the H1N1 strain, 33-year-old Judy Trunnell of Texas, fell ill while in late-stage pregnancy. She died May 5 after falling into a coma. Her healthy baby girl was delivered by C-section.
Why does pregnancy put women at special flu risk? Emory University's Dr. Kevin Ault told the Associated Press that pregnancy causes changes to women's respiratory and immune systems that may make it more difficult for them to rid themselves of influenza infection. And the World Health organization recently stated that pregnant women may be "at increased risk for severe disease, potentially resulting in spontaneous abortion and/or death, especially during the second and third trimesters of pregnancy."
The risk of H1N1 during pregnancy has even led some health officials in Britain and Switzerland to advise that women consider delaying pregnancy during an H1N1 outbreak. No such call has come from U.S. health officials, however.
There's also the issue of whether a flu shot might confer some protection to newborns, who have relatively undeveloped immune systems. A study published recently in the New England Journal of Medicine found just such a transfer of protection among a group of Bangladeshi women and their offspring who received the seasonal flu vaccine.
Dr. Marc Siegel, an associate professor of medicine at New York University Langone Medical Center in New York City, agreed that pregnant woman should be of special concern. "Pregnant women are semi-immunocompromised, they are a target population for any infection," he said. "It is not surprising that they are at risk of flu, any flu."
In addition, today's pregnant women are younger than women born before 1957, who appear to have some immunity to the new H1N1 swine flu, Siegel said. "I put pregnant women up near the top of the list of those who should get the H1N1 vaccine," he said.
Women should not be afraid of being vaccinated against the H1N1 flu, he added. "Any fear of vaccines is greatly outweighed by the benefit of being inoculated against an emerging virus," he said. "The best way to protect a pregnant women is for everyone around her to be vaccinated in addition to her."
Another expert agreed that moms-to-be should be at the head of the line for the H1N1 shot.
"In addition, because of the greatly increased risk of death for pregnant women from either the seasonal flu or from the H1N1 swine flu, those infected with an influenza virus should [also] be promptly treated with appropriate anti-viral agents," said Dr. Pascal James Imperato, dean and distinguished service professor in the School of Public Health at SUNY Downstate Medical Center in New York City.
The seasonal flu vaccine will offer no protection against the H1N1 swine flu, Imperato added. "This means that some groups in the population will need to receive more than just one flu shot in order to be protected against all of the influenza strains in circulation," he said.
There's also the lingering memory of the 1976 swine flu vaccination program, during which some 500 Americans came down with a rare neurodegenerative condition called Guillain-Barre syndrome, which many experts believe was linked to the shot. Twenty-five of those 500 people died.
"The potential for more severe illness and many more deaths caused by this new strain of influenza weighs heavily on our minds -- as does the unfortunate outcome of the 1976 swine flu vaccination program," said CDC spokeswoman Arleen Porcell-Pharr.
But the H1N1 flu vaccine will be very much like seasonal flu vaccines, which have an excellent safety profile, Porcell-Pharr said. "However, no vaccine is 100 percent safe. This vaccine will be no exception," she added.
If the vaccines are recommended for use, those who choose to be inoculated will receive information sheets describing the vaccines' risks and benefits, signs of side effects to look for after vaccination, and information on how to report adverse events, she added.
"We will be watching very closely for any signs that the vaccine is causing unexpected side effects, and we have systems in place to investigate those signals rapidly," Porcell-Pharr said.
For more information on swine flu, visit the U.S. Centers for Disease Control and Prevention.