Opinion | Ever since the U.S. Centers for Disease Control and Prevention (CDC) began recommending that all Americans six months of age and older get an annual flu shot, it’s been touted as the best method of preventing influenza.
While it’s true that influenza is a highly infectious airborne disease, controversy exists over the use of influenza vaccines, commonly known as flu shots, for its prevention, and this is particularly true for high-risk groups like seniors.
For starters, more than 80 percent of the respiratory influenza-like illness infections that occur during flu season are not actually caused by type A or type B influenza.1 A flu shot, therefore, will not prevent the vast majority of respiratory infections caused by bacteria and other types of viruses during the flu season.
Further, there are hundreds of influenza viruses, and they’re constantly changing, which means each year health officials must make an educated guess as to which strains are most likely to circulate in the upcoming flu season. The three or four type A and type B influenza viruses that are chosen are then added to that year’s seasonal flu shot, with varying and often disappointing results.
It’s also often stated that influenza vaccination reduces hospitalizations and deaths among the elderly, but research published in the Annals of Internal Medicine calls this into serious question.
Flu Vaccine Doesn’t Reduce Hospitalizations, Death in Seniors
An observational study funded by the National Institute on Aging and conducted by researchers from the University of California, Berkeley, the University of California, Santa Cruz and Clemson University reviewed data from 170 million episodes of care and 7.6 million deaths among adults aged 55 to 75, from the year 2000 to 2014.
The goal was to determine the effectiveness of the influenza vaccine in reducing hospitalizations and deaths among elderly people in the study area in England and Wales, using a research design that reduced the possibility of bias and confounding.
While turning 65 was associated with a significant increase in the rate of seasonal influenza vaccination, the study’s authors stated that “no evidence indicated that vaccination reduced hospitalizations or mortality among elderly persons.”2 The researchers concluded:
Current vaccination strategies prioritizing elderly persons may be less effective than believed at reducing serious morbidity and mortality in this population, which suggests that supplementary strategies may be necessary.3
‘Supplementary Strategies’ Include Vaccinating Children
While stating that influenza vaccines did nothing to reduce hospitalizations and death rates among seniors, the researchers offered questionable “supplementary strategies” as a solution—namely increasing vaccination among other populations:
Our findings raise questions … about the overall effectiveness of a vaccination strategy that is limited to standard vaccines and focuses too much on elderly persons. Supplementary strategies, such as vaccinating children and others who are most likely to spread influenza, may also be necessary to address the high burden of influenza-related complications among older adults.4
However, it’s important to note that flu shot effectiveness is typically low across all age groups, ranging from 10 percent during the 2004 to 2005 flu season to 60 percent during the 2010 to 2011 flu season. Further, in 10 out of 14 flu seasons between 2004/2005 and 2017/2018, overall influenza vaccine effectiveness was less than 50 percent.5
During the 2019 to 2020 flu season, the interim estimates released by the CDC state that the overall estimated effectiveness of seasonal influenza vaccine from October 23, 2019 to January 25, 2020 was just 45%.6
Likewise, during the 2018 to 2019 flu season, the vaccine failed to offer any protection more than half the time, and for adults over 50, it was more or less useless, offering a mere 24 percent effectiveness rate against all influenza types.7 Even the CDC stated, “ … more effective influenza vaccines are needed.”8
There are risks of side effects, as well, including among children. A 2009 U.S. study compared health outcomes for children between six months and age 18 who did and did not get annual flu shots over eight consecutive flu seasons and found that children who had received inactivated influenza vaccinations had a three times higher risk of influenza-related hospitalization, with asthmatic children at greatest risk.9
This evidence suggests that annual flu shots may lead to reduced protection against influenza and even increase risks for coming down with influenza.10
Study Bias High Among Vaccine Studies in Elderly
The featured study is important, in part, because it attempted to eliminate bias that has been widespread among previous research into flu vaccines among the elderly.
For instance, a 2006 study found seniors who received influenza vaccines had a 44 percent reduced risk of dying during flu season compared to unvaccinated seniors, which sounds promising, until you learn that those who were vaccinated were also 61 percent less likely to die before the flu season ever started—a finding attributed to the “healthy user” effect.1112
“The reductions in risk before influenza season indicate preferential receipt of vaccine by relatively healthy seniors,” the researchers noted. “In this study, the magnitude of the bias demonstrated by the associations before the influenza season was sufficient to account entirely for the associations observed during influenza season.”13
A 2019 systematic review published in the journal Vaccine also found evidence of widespread bias. Out of 22 studies, nine percent were found to be at moderate risk of bias, 59 percent were at serious risk of bias and 32 percent were at critical risk of bias. “For all-cause hospitalization outcomes, we found a wide range of results, mostly deemed at serious risk of bias,” the researchers noted.14
Flu Vaccination’s Dismal History Among Seniors
Despite the CDC’s continued assurance that annual flu shots are the best bet for seniors to avoid getting infected with type A or B influenza, the product has a dismal history in terms of effectiveness. Research published in 2006 analyzed influenza-related mortality among the elderly population in Italy that was associated with increased vaccination coverage between 1970 and 2001.15
Researchers found that after the 1980s, there was no corresponding decline in excess deaths among the elderly, despite rising influenza vaccine uptake. According to the authors, “our study challenges current strategies to best protect the elderly against mortality, warranting the need for better controlled trials with alternative vaccination strategies.”16
The Flucelvax vaccine introduced during the 2017-2018 flu season is grown in dog kidney cells rather than chicken eggs. Touted as a new-and-improved flu shot that would protect more people, U.S. Food and Drug Administration research found no significant difference between it and the conventional flu shot in protecting seniors.
While flu shots overall had only 24 percent effectiveness in preventing influenza-related hospitalizations in people aged 65 and older, the Flucelvax vaccine had an effectiveness rate of only 26.5 percent in that population.17
Health officials also frequently state that if you get the influenza vaccine, it will lessen disease severity should you get infected with type A or B influenza viruses. But a 2017 study by French researchers found such claims not to be true. Looking at data from vaccinated and unvaccinated elderly patients diagnosed with influenza, all they found was a reduction in initial headache complaints among those who had been vaccinated:18
Compared to non-vaccinated influenza patients, those who had been vaccinated had a slightly reduced maximum temperature and presented less frequently with myalgia, shivering and headache.
In stratified analyses, the observed effect was limited to patients infected with A(H3) or type B viruses. After adjusting by age group, virus (sub)type and season, the difference remained statistically significant only for headache, which was less frequent among vaccinated individuals … Our findings reinforce the need for influenza vaccines providing better protection.
Echoing other studies, a systematic review and meta-analysis published in The Lancet Infectious Diseases similarly stated, “Evidence for protection [from influenza vaccines] in adults aged 65 years or older is lacking.”19
This article was reprinted with the author’s permission. It was originally published on Dr. Mercola’s website at www.mercola.com.
Note: This commentary provides referenced information and perspective on a topic related to vaccine science, policy, law or ethics being discussed in public forums and by U.S. lawmakers. The websites of the U.S. Department of Health and Human Services (DHHS) provide information and perspective of federal agencies responsible for vaccine research, development, regulation and policymaking.
1 NVIC, Influenza Quick Facts.
2 Annals of Internal Medicine March 3, 2020.
3 Annals of Internal Medicine March 3, 2020, Conclusion.
4 FierceHealthcare March 4, 2020.
5 NVIC, Influenza Disease & Vaccine Information.
6 MMWR Weekly February 21, 2020 / 69(7);177–182.
7 CDC.gov MMWR February 15, 2019; 68(6);135–139.
8 See Footnote 6.
9 Science Daily May 20, 2009.
10 PNAS January 18, 2018; 115(5): 1081-108.
11 International Journal of Epidemiology April 1, 2006; 35(2): 337-344.
12 Scientific American October 18, 2012.
13 See Footnote 11.
14 Vaccine May 27, 2019, Volume 37, Issue 24, Pages 3179-3189.
15 Vaccine 2006 Oct 30;24(42-43):6468-75
17 FiercePharma June 27, 2018.
18 Vaccine April 11, 2017; 35(16): 2076-2083.
19 The Lancet Infectious Diseases, January 2012, Volume 12, Issue 1, Pages 36-44.