|
medpundit |
||
 |
 |
|
Wednesday, February 16, 2005The flu vaccinations that doctors hoped would save the lives of fragile elderly people have apparently failed to lower death rates, U.S. researchers said on Monday. More people whose health could be put at risk by influenza have heeded the call to get vaccinated before flu season, but the death rate during the winter flu season remained the same rather than declining, they said. Based on U.S. mortality rates from 1968 to 2001, the study by the National Institute of Allergy and Infectious Diseases found no correlation between increasing vaccination rates after 1980 and declining death rates in any age group. .....While the vaccination rate in 2001 rose to 65 percent among elderly Americans from around 20 percent before 1980, the rate of excess winter deaths has remained flat instead of declining by an expected 40 percent. The study does raise some questions: Influenza vaccination coverage among elderly persons (65 years) in the United States increased from between 15% and 20% before 1980 to 65% in 2001. Unexpectedly, estimates of influenza-related mortality in this age group also increased during this period. .....For people aged 65 to 74 years, excess mortality rates in A(H3N2)-dominated seasons fell between 1968 and the early 1980s but remained approximately constant thereafter. For persons 85 years or older, the mortality rate remained flat throughout. Excess mortality in A(H1N1) and B seasons did not change. All-cause excess mortality for persons 65 years or older never exceeded 10% of all winter deaths. We attribute the decline in influenza-related mortality among people aged 65 to 74 years in the decade after the 1968 pandemic to the acquisition of immunity to the emerging A(H3N2) virus. We could not correlate increasing vaccination coverage after 1980 with declining mortality rates in any age group. Because fewer than 10% of all winter deaths were attributable to influenza in any season, we conclude that observational studies substantially overestimate vaccination benefit. Mother nature apparently did a better job of immunizing the elderly than all of our flu vaccines. posted by Sydney on 2/16/2005 08:04:00 AM 0 comments 0 Comments: |
|
