Flu Shot Strategy Challenged By Study Favoring School Kids, Parents
Most flu transmission happens among children ages 5 to 19, and the virus is then carried into communities through parents ages 30 to 39, according to the study published today in the journal Science. Children younger than 5 and most adults older than 19 arent critical spreaders of infection and their vaccinations shouldnt be the top priority as set out by U.S. guidelines, the study found.
Swine flu vaccines in the U.S. are delayed by manufacturing difficulties, and just 45 million doses of the governments 195 million-dose order will be available by mid-October, U.S. health officials reported this week. That may mean the shots should be given to targeted groups first instead of the general population. The U.S. plan focuses vaccine efforts on health-care workers, pregnant women and people ages 6 months to 24 years.
“You can stop the transmission chain very effectively by vaccinating the schoolchildren,” said Jan Medlock, an epidemiologist and assistant professor of mathematics at Clemson University in Clemson, South Carolina, and lead author of the study, in an audio interview with Science. “The big difference is that we found it optimal to exclude people under 5. Theres not a significant amount of transmission among them.”
The study, funded by a $650,000 grant from the National Science Foundation, used mathematical models based on data from past pandemics to find the best ways to reduce deaths, infections, years of life lost and costs. Under all measures studied, vaccinating schoolchildren and their parents was most effective.
CDC Recommendations
“Our recommendations are based on the actual experience of the epidemiology of this outbreak since late April and May,” said Tom Skinner a spokesman for the U.S. Centers for Disease Control and Prevention, the Atlanta-based agency responsible for U.S. vaccine recommendations. “If we see any changes in the way this virus is behaving as the influenza season unfolds, Im sure we would step back and make any changes that were necessary.”
Targeting specific age groups for vaccination is difficult for doctors and confusing to patients, said William Schaffner, chairman of the department of preventive medicine at Vanderbilt University School of Medicine in Nashville, Tennessee. Some patients dont realize they are in a target group, and people not in those groups may never return to get vaccinated when larger supplies of vaccine are available, he said.
Include Everyone
“The only sin is vaccine left in the refrigerator,” Schaffner told a CDC advisory panel when it met July 29 to vote on the recommendations. When limited shots are available, they should be given to anyone who seeks them to get the most people vaccinated, he said.
Swine flu, also known as H1N1, has reached more than 170 countries and territories in the four months since being identified, the World Health Organization said. The virus causes similar symptoms as seasonal strains. It has so far resulted in “slightly worse” than normal flu seasons, with increased hospitalizations and cases of severe illness, the Geneva-based agency said in an Aug. 12 release.
The median age of those with the pandemic virus has been 12 to 17 years, the WHO said on July 24, citing data from Canada, Chile, Japan, U.K. and the U.S.
((Click here to view the scheduled 3:30 p.m. New York time news conference about guidelines for college students.))