Date: 12/30/2003 2:48:52 AM ( 14y ago ) Hits:11325
FLU SHOTS...DO THEY REALLY WORK?
By Kristine M. Severyn, R.Ph., Ph.D.
Every autumn the elderly and other high risk groups are encouraged to receive influenza vaccine (flu shots). Congress authorized Medicare funding for flu shots in 1993, believing that vaccination costs are less than hospitalization costs related to influenza complications. Was Congress misled when it authorized this $80 million per year Medicare flu shot entitlement? Have vaccine recipients been misled?
Although influenza is associated with more disease, hospitalization, and death in "at risk" populations, no adequate controlled studies exist which prove that influenza vaccine reduces the incidence of influenza in these groups (1).
CDC Crystal Ball
Influenza virus strains mutate, necessitating a new vaccine each year. Technicians affiliated with the Centers for Disease Control and Prevention (CDC) collect influenza viruses from pigs and people in foreign lands, e.g. China. CDC personnel then attempt to predict which viruses will infect people in the U.S. the following yearÖthe CDC crystal ball. These CDC-selected viruses are distributed to vaccine manufacturers early in the year for influenza vaccine production for administration that autumn.
How Good is the CDC Crystal Ball?
Predicting which influenza viruses from China, for instance, will infect people in Dayton, Ohio a year later involves a fair amount of guesswork. Flu shot history is replete with examples of poor matches between influenza viruses in the vaccine and those actually infecting people.
For Example in the 1994-1995 flu season, the CDC reported that 43% of isolated influenza samples for the predominant virus (type A(H3N2) ) were not similar to that in the vaccine. Likewise, for another type A virus (HINI), 87% of samples were not similar to that in the vaccine. For influenza B, 76% of isolated samples were not similar to that in the vaccine (2).
The CDC crystal ball also erred during the 1992-1993 influenza season when 84% of the isolated influenza samples for the predominant virus (A(H3N2)) were not similar to that in the vaccine (3).
Despite its poor track record in predicting which influenza viruses will infect communities, the CDC claims that influenza vaccine is "approximately 70%" effective in preventing influenza in "healthy persons less than 65 years of age" If "there is a good match between vaccine and circulating viruses" (4). Depending on the study cited, vaccine efficacy actually ranges from a low of 0% to a high of 986% (5). And, as illustrated above, the CDC often finds it difficult to match vaccines with circulating viruses.
Poor Vaccine Efficacy in the Elderly
Influenza vaccine efficacy drops to 30-40% among the elderly, this group being the main "target" for flu shots. CDC attributes lack of influenza vaccine efficacy in the elderly to their "decreased immunologic response." (6, 7)
Past studies of Type A (H3N2) influenza vaccine in nursing home patients yielded an average of only 27% efficacy, with four studies demonstrating vaccine efficacy at 0, 2, 8 and 9% (6). Poor vaccine efficacy can even occur when the vaccine virus is "essentially identical" to that causing the outbreak (5). For influenza B vaccine, studies range from 0% to 36% effective, averaging 21% (6).
To justify its recommendation that all elderly persons receive flu shots, the CDC asserts that even though the vaccine does not prevent influenza very well, "the vaccine can be 50-60% effective in preventing hospitalization and pneumonia and 80% effective in preventing death" (4).
This optimistic scenario is clouded by results of the congressionally mandated $69 million 1988-1992 Medicare Influenza Vaccine Demonstration project. This study, intended to promote Medicare-funded flu shots, yielded a disappointing 31-45% effectiveness "in preventing hospitalization for any pneumonia" during three influenza seasons (4). Results for the 1989-1990 season were described as "mixed at best", with "medicare paymentsÖ..significantly higher for those who had been vaccinated". (9)
Government agencies "calculated" an economic benefit of flu shots to Medicare by manipulating numbers in a computerized simulation until desirable results were obtained. The CDC reported that its theoretical assumptions did not include all vaccine-related costs (8). Other recently publicized medical studies with similar economic claims for flu shots have been funded by a vaccine manufacturer (10, 11).
Several studies and government projections (12) confirm that, with or without a flu shot, pneumonia and influenza hospitalization rates for the elderly are less than 1% during the influenza season. This means that, regardless of vaccination status, more than 99% of people weather a bout of flu without requiring hospitalization. Even the current director of CDC's national Immunization Program, Dr. Walter Orenstein, reported at an influenza conference that the "at risk" population for influenza complications is small (5).
Do Flu Shots Really Prevent Death in the Elderly?
Considering that more than 90% of pneumonia and influenza deaths occur in persons 65 years of age or older, but that about 65% of all deaths (from any cause) occur in this age group anyway, it is nearly impossible to prove if flu shots significantly increase life expectancy in the elderly. Indeed one study of elderly Medicare patients in Ohio and Pennsylvania showed "no demonstrated effect of influenza vaccine in preventing death or limiting the length of hospital stay" (13).
Health authorities in other countries do not share the U.S. public health community's enthusiasm for influenza vaccine. At one CDC-sponsored influenza symposium a British researcher stated, "The [influenza vaccine] recommendations are strong in certain countries, but weak in others, since not all authorities are convinced of the benefits of immunization" (emphasis added). He deplored the "unsatisfactory situation" of poor influenza vaccine efficacy, which "compares unfavorably with other virus vaccines" (14) Even CDC officials confessed that "influenza vaccines are still among the least effective immunizing agents available, and this seems to be particularly true for elderly recipients". (6)
Congress and the American taxpayer have been defrauded about the alleged advantages of flu shots. Instead of being an effective prevention, evidence indicates that flu shots may be useless. Although endorsed and funded by federal and state governments the shots seem only to benefit the companies who make them, public health bureaucrats who promote them, and medical personnel who administer them.
Fiebach N, Beckett W. prevention of respiratory infections in adults: influenza and pneumococcal vaccines. Arch Intern Med. 1994: 154: 2545-57.
Update: influenza activity-worldwide, 1995. MMWR 9/9/95; 44(35): 644-45, 651-52.
Update: influenza activity-United States and worldwide, 1993. MMWR 10/1/93; 42(38): 752-55.
Prevention and control of influenza: recommendations of the Advisory Committee on Immunization Practices 9ACIP). MMWR 4/21/95; 44(rr-3).
Dowdle WR. Influenza Immunoprophylaxis after 30 years' experience. In: Nayak DP, ed. Genetic Variation Among Influenza Viruses. New York: Academic Press, 1981: 525-34.
Arden NH et al. Experiences in the use and efficacy of inactivated influenza vaccine in nursing homes. In: Kendal AP, Patriarca PA, eds. Options for the Control of Influenza. New York: Alan R. Liss, 1986: 155-68.
Influenza. In: Atkinson W, et al, eds. Epidemiology and Prevention of Vaccine-Preventable Diseases. Centers for Disease Control and Prevention, Department of Health and Human Services, U.S. Public Health Service, 1995; 173-88
Final results: Medicare Influenza Vaccine Demonstration-selected states, 1988-1992. MMWR 8/13/93: 42(31): 601-4
Kidder D, Scmitz R. Measures of cost and morbidity in the analysis of vaccine effectiveness based on Medicare claims. In: Hannoun C, et al. Eds. Options for the Control of Influenza 11. Amsterdam: Excerpts Medica, 1993; 127-33
Nichol KI et al. The efficacy and cost effectiveness of vaccination against influenza among elderly persons living in the community. New Engl. J Med. 1994; 331(12): 778-84.
Nicol KI et al. The effectiveness of vaccination against influenza in healthy, working adults. N Engl. J Med. 1995; 333(14): 889-93.
Flu prevention campaign underway. Health Care Financing Administration press office, phone: (202) 690-6145. HHS News, 10/16/95. U.S. Department of Health and Human Services.
Strikas R, et al. Case control study in Ohio and Pennsylvania on prevention of hospitalization by influenza vaccination. In: Hannoun C, et al. eds. Options for the Control of Inlfuenza 11. Amsterdam: Excerpta Medica, 1993: 152-60.
Ahmeida ETSB, et al. Inactivated influenza vaccine: past, present, and future, In: Hannoun C, et al. Eds. Options for the Control of Influenza 11. Amsterdam: Excerpta Medica, 1993; 371-2.
Copyright 1995 Ohio Parents for Vaccine Safety
This article appeared in the Autumn 1995 issue of Vaccine News, the national newsletter of Ohio Parents for Vaccine Safety. This article is available in brochure form and can be obtained from: Ohio Parents for Vaccine Safety, 251 Ridgeway Dr. Dayton, Ohio, 45459. Phone (937) 435-4750.