What is flu shot?
The Influenza vaccine, also known as a Flu Shot, is an annual vaccine to protect against the highly variable influenza virus
There are two types of flu vaccines, the injection (with killed virus) and nasal spray vaccines (containing live, but weakened, virus).
Each year, the influenza virus can change slightly, making the vaccine used in previous years ineffective.
The vaccine is generally effective against the influenza virus within two weeks of administration.
The vaccine is only effective against the strains of the virus that match the vaccine.
The effectiveness of the flu vaccine is dependent upon the extent of the match between the virus strains used to prepare the vaccine and those viruses in actual circulation. The age and health status of the individual also play a role in determining the effectiveness of the vaccine.
What is flu?
The flu (or common flu) is a viral infection that is spread from person to person in secretions of the nose and lungs, for example when sneezing. Medically, it is referred to as influenza. Flu is a respiratory infection, that is, an infection that develops primarily in the lungs. Respiratory infections caused by other viruses often are called flu, but this is incorrect. Influenza usually causes higher fever, more malaise, and severe body aches than other respiratory infections. Although other viruses may cause these symptoms, they do so less commonly.
Influenza viruses are divided scientifically into three types, designated A, B, and C. Influenza types A and B are responsible for epidemics of respiratory illness that occur almost every winter. Influenza type C usually causes either a very mild respiratory illness or no symptoms at all; it does not cause epidemics and does not have the severe public-health impact of influenza types A and B. Type A viruses are divided into subtypes and are named based on differences in two viral surface proteins called hemagglutinin (H) and neuraminidase (N). There are 16 known H subtypes and nine known N subtypes.
The flu is a common illness. Every year in the United States, on average
5%-20% of the population gets the flu,
more than 200,000 people are hospitalized from flu complications,
about 36,000 people die from the flu or its complications.
Why vaccinate for the flu?
The flu is highly infectious and is a serious viral respiratory infection. Whereas with other viral respiratory infections the symptoms usually are mild and most people can continue working or going to school while ill, with the flu, the symptoms are severe and prolonged and cause individuals to miss days of work or school. The infection stresses the body. In addition, superinfections may occur. Superinfections are bacterial infections that occur on top of a respiratory infection. Bacterial respiratory infections also are a serious type of infection, and the simultaneous viral and bacterial infection can overwhelm the function of the lungs and the body. Among the elderly and the very young, it can cause death. Because of its infectiousness, morbidity (severity of symptoms and time lost from work or school), and the potential for death, it is important to prevent the flu by vaccination. Although there are medications to treat the flu, they are expensive, not as effective as vaccination, and need to be started within 24-48 hours of the start of symptoms.
Wow very interesting research-There is not enough evidence to recommend universal vaccination against influenza in healthy adults.
The Cochrane Collaboration’s examination of flu vaccines in healthy adults, a body of literature spanning 25 studies and involving 59,566 people, finds an annual flu shot reduced overall clinical influenza by about six percent.
How many diseases are important enough to have their own season? Not many, but we do have one, and it strikes every year: the flu. Arriving in the fall and exiting in the spring, flu season strikes with the predictability of clockwork. For some the flu might be a mild inconvenience, perhaps embraced as a way to stay home and get a few days couch side wrapped in the unpleasantness of high fever, aches, sniffles, and daytime reality TV. Yet for others, usually the elderly or those with compromised immune systems, the flu can be deadly. It can lead to hospitalizations, pneumonia, and sometimes death.
Victoria might be on an island but its residents are not immune to viruses. So we prepare, stockpiling flu vaccines and drugs, hectoring the public to get an annual flu shot and, with a new twist this season, giving an ultimatum to health workers: either get a flu shot or wear a mask while at work.
BC’s Provincial Health Officer Dr Perry Kendall is betting that our province’s health workers need such strong medicine to stop them passing on the flu to their patients, and he’s launched the most aggressive flu policy in Canada, one which could set the trend for the rest of the country. But Dr Kendall and his public health colleagues around the world are facing an uphill struggle as their anti-flu policies and public health mandates are increasingly criticized because of the strong-armed ways they are being enforced. Add to this the growing cynicism around the fear-mongering of recent flu pandemics, and the overzealousness with which vaccines are promoted, and you have a recipe for a cynical public.
But of most concern is the determination by some respected international scientists and researchers that annual influenza campaigns are likely an utter waste of time and money.
Half the story
Don’t be like me, and be taken for a fool.” That’s the advice that Dr Tom Jefferson offers when I ask him about his research around flu vaccines and flu drugs. He has spent over a decade examining and summarizing the evidence around one of the most stockpiled drugs in the world, oseltamavir (also know as Tamiflu), and tells me over the phone from his office in Rome: “I can only say that I have acted as an unpaid salesperson for Roche [the maker of antiviral drug Tamiflu] for the last ten years!”
Now a researcher with the Cochrane Collaboration, working on acute respiratory infections and vaccines, Jefferson essentially confirmed what I’d heard from other researchers: that much of the published research on all kinds of drugs and treatments found in peer-reviewed medical journals is incomplete. It only gives half the story.
In the case of Tamiflu, a drug that is supposed to prevent the spread and the severity of the flu, Jefferson and colleagues have proven that the drug’s published dataset delivers a biased and misleading picture of the drug because the company has only released a portion of it. If your job is to find, summarize and synthesize what is in the published literature—as it is for a meta-analyzer like Jefferson—incomplete data sets are a major problem. Over the past few years he and his colleagues have frequently asked Roche to release Tamiflu’s full data set, but so far the company offers up mostly “the dog ate my homework”-type of excuses for why they can’t cough it up.
The scourge of hidden data is not new in medical research, but this just adds to the sense of how shaky the global influenza apparatus might be. When the companies that study the drug stand to gain billions on how that research is presented, we have a problem. Jefferson has written that poor science, coupled with “media business, pharma business, pandemic business and unaccountable decision-making,” are making a mockery of global policies around the flu.
The problem starts with a semantic one, where “the flu” is equated to “influenza,” a falsity which Jefferson writes “is now so ingrained in the popular and sometimes professional mind that governments and public fall prey to its greatest consequence: that of overestimating the impact of influenza, which is usually a benign self-limiting infection.”
Beyond semantics, we need to consider the basic epidemiology of the flu. There are over 200 viruses that cause influenza and influenza-like illness and can produce symptoms similar to the everyday flu. It is estimated that 80 percent of flu-like illness reported during the “flu season” is not caused by influenza. As well, influenza viruses constantly evolve and mutate and since it takes up to nine months to develop the right vaccine, by the time flu season arrives, the flu shot may or may not match strains circulating.
Which is to say, fighting the flu is largely a hit-and-miss affair
Jefferson wants to make sure flu policies affecting millions of people are based on proper, undeniable proof. Of the many health authorities around the world who support mass flu vaccine campaigns—those he irreverently refers to as “bioevangelists”—he claims the science shows they are mostly wrong: “There is no reliable evidence that inactivated influenza vaccines [the standard types of vaccines of today] affect either person-to-person spread of influenza or complications such as death or pneumonia…and [this] relates both to healthcare workers, community-dwellers and people in institutions.”
The flu vs. influenza-like illness
Jefferson didn’t intend to become a flu researcher. He spent the early part of his medical career as a physician in the British Army, serving tours in the Falklands, Bosnia and Croatia. A wide handlebar mustache that some said made him a caricature of the Modern Major General was perhaps a decoy, hiding the fact he was a rebel at heart.
In the spring of 1984, Jefferson was stationed in Germany with the 3rd Battalion Royal Anglian Regiment. He was ordered early one morning to report to his commanding officer, who told him that the Army had a terrible medical problem that needed his immediate assistance.
What was it? A new tropical disease needing investigation? A spate of injuries due to hostilities? No, nothing as exciting as that. The CO said that his unit had a terrible problem of acute respiratory disease, with the kind of chills, wheezing and high temperatures associated with garden-variety flu. He ordered Jefferson to “look into it.”
With access to decent surveillance data collected from the barracks by the Army’s medical teams, Dr Jefferson was shocked at the numbers, saying, “We had a system to calculate the working days lost, and it was astronomical.” That clearly stoked his interest: “Most other medical researchers were interested in fancy stuff, exotic stuff, people killed in action and so on, as that was the stuff that got into the newspapers. But something as simple as colds and flu—which knocked out a brigade’s worth of soldiers every year—now that was something worth looking into.”What Jefferson saw that day at the base was a sudden and inexplicable increase in ILI—influenza-like illness, and it left him scratching his head.
“I couldn’t really understand what was happening. There was no real activity outside the battalion—soldiers had it, the families had it, the children had it—wives had it…and I thought, what is this?” He recalls that at that time, a rumour was circulating that the battalion was going to be deployed to Northern Ireland, a tour of duty they completed several times in the 1970s and ’80s. The regiment had lost 18 soldiers during these previous deployments, a fact fresh in the minds of the soldiers and their families. The upcoming deployment was understandably causing a lot of stress on the base and Dr Jefferson surmised that stress “perhaps explained why the battalion was hit with a high incidence of ILI.”
Five years later, he was able to work alongside Dr David Tyrrell who was tutored by some of the original discoverers of the influenza virus. Jefferson says that one of the most vital things he learned from Dr Tyrrell is the imprecision of the word “flu.” Tyrrell said that what people referred to as “the flu” was a “dangerous colloquialism,” and he stressed it was more appropriate to call the collection of symptoms “influenza-like illness.” As Jefferson says, “the confusion between influenza and influenza-like illness has led to an obsession with a single agent [the influenza virus] which is not based on any sound evidence.” With most of the extra illness suffered during flu season not caused by a verifiable flu virus, the situation, says Jefferson, is “potentially dangerous and misleading” because even if the best vaccine can prevent a proven flu virus, you’re only able to help a small portion of the people who become ill. Jefferson served with the UN during the Yugoslav crisis, and reports: “I also observed the effects of ILI in terms of working days lost on British and UN soldiers.” In his opinion, “High rates of ILI were associated with stress, overcrowding and, of course, combat.”
Just not enough evidence
Nearly two decades later, Jefferson worries about the absence of quality research around other potential causes of flu-like illness, including the role of stress. Compared to the serious global money-makers—the vaccines and antivirals which bring billions to the coffers of drug companies every year—something as simple as stress and its relation to the flu is simply not studied. There are some efforts to study methods to prevent virus transmission (masks and handwashing), but compared to the huge annual drug and vaccine enterprise focused on a virus, these efforts seem pitifully small.
The fact that a physician steeped in military tradition and respect for authority would turn out to be one of biggest anti-authoritarians in the influenza world is a delicious irony. Jefferson admits it is “absolutely heresy” to even imply that stress may play a role in causing the flu. He adds, it “undermines the living of very many people, and goes against the dogma of people selling vaccines and pills.”
The best way to counter the dogma is to find the most reliable evidence—preferably from an overview of all relevant studies, known as a meta-analysis. And that’s Jefferson’s game as part of the Cochrane Collaboration (www.cochrane.org), an international organization of consumers, scientists and researchers, gathering and systematically examining all the studies ever conducted to see how well a treatment works. Cochrane’s work is unique in at least two ways: it won’t take money from the drug or vaccine manufacturers to fund its research, and it uses the highest gold-standard methodologies when synthesizing research.
The Cochrane examination of flu vaccines in healthy adults, a body of literature spanning 25 studies and involving 59,566 people, finds an annual flu shot reduced overall clinical influenza by about six percent. It would reduce absenteeism by only 0.16 days (about four hours) for each influenza episode, a small effect given that the average flu bout lasts five to seven days. What was most illuminating was the authors’ conclusion: “There is not enough evidence to recommend universal vaccination against influenza in healthy adults.”
Jefferson and his colleagues found that most influenza studies are poorly designed and fail to prove the influenza vaccine is effective or safe for certain groups, such as the elderly and children under two. (In Canada, parents might be surprised to hear that Canada’s National Advisory Committee on Immunization recommends flu shots for kids six to 23 months old.)
Canada isn’t the only country with recommendations out of sync with the evidence. Earlier this summer, the UK’s National Health Service reported that they needed to find 1000 extra school nurses to give the flu vaccine to healthy children for the upcoming flu season. This was in response to government plans to expand the vaccination program to all children aged two to 17.
This decision was based on a series of computer models estimating that if 30 percent of the population were vaccinated for the flu, then there could be a reduction of 2000 deaths and 11,000 fewer hospital admissions. Expanding the program to children, seniors, pregnant women, and people who are considered at “higher risk,” would cost about $150 million per year, as reported in the UK’s Guardian newspaper. But will all that money actually deliver fewer deaths and hospitalizations?
The answer is “probably not.” Jefferson and others contend that using a computer model as the justification for an expanded flu vaccine program is very problematic. Tweak any of the assumptions in the model and you get what you want. Such an expanded program surely would please British-based pharmaceutical giant GlaxoSmithKline, a big player in the flu game—and should remind us of the politics of money behind any large public health program.
(Source- focusonline)
