Double-Edged Sword: Swine Flu and Vaccines

By guest author Terry Doherty and Ilene, your editor

Terry Doherty is the Research Program Coordinator in the Depts of Biomedical Sciences and Academic Affairs at Cedar Sinai in Los Angeles, California.

Double-Edged Sword: Swine Flu and Vaccines

There’s plenty that is unknown about the swine flu and the swine flu vaccine.  If searches on the internet are any indication, deciding whether or not to be vaccinated may be a tough, emotionally charged decision for many people.  So how – without having the background to write a swine flu grant proposal, conduct the research, and get the thing published in the New England Journal of Medicine – do we decide whether or not to get a swine flu shot?  

One way is to attempt to evaluate and weigh the risks of the vaccine against the risks of the flu.  That is how I approach the subject, but it’s easier said than done.  As is often the case with medical interventions, the risks are not fully known. And even if we could carefully assess the risks, our underlying assumptions may be wrong.  Percent risks are averages collected by studying large populations.  We may not be one of the statistical average.  Then there are the gaps in the available data, and own biases and belief systems.  Our view of the world affects our analysis and often we are not even aware of how large of an effect those biases may play.   

In Vaccine War: Autism, Flu and Science, TIME, Maia Szalavitz discusses how emotion and biases play a large part in our risk-benefit assessments:

Just in time for the national roll-out of the new H1N1 flu vaccine, Wired Magazine and the Atlantic have weighed in on the ongoing vaccine war: Wired has a profile of Paul Offit, a vaccine researcher and pediatrician who has consistently spoken out in favor of vaccination and pointed to the lack of evidence linking vaccines and autism; the Atlantic checks in with a piece questioning the science suggesting that flu vaccines and antiviral drugs prevent people from dying.

Both articles have elicited heated debate all over the Web: Amy Wallace, who wrote Wired’s piece, excerpted below, has received vitriolic criticism and attacks from vaccine opponents, setting records for page views…

This debate over vaccination doesn’t seem likely to end any time soon. For critics, vaccines have become a touchstone for cultural anxieties and a not entirely unjustified mistrust of government and big business. No matter what evidence researchers provide supporting the safety of vaccination and its clear benefit to global public health, opponents remain convinced that the vaccine industry is tainted and biased by commercial pressures and that anyone who supports vaccination must have financial motives.

But for those who are concerned about health and safety, these articles and the related discussions offer a fascinating view of the controversy.  If we are to have a rational conversation about the best way to fight flu, infectious disease and autism, we need to recognize that these are scientific questions and use the best research—not the data that supports our preconceived views—to answer them. 

Due to its newness and lack of conclusive information, the role of biases in affecting decision making-process may be especially true for the H1N1 vaccine.  Although several government-sponsored projects are attempting to evaluate the safety of the vaccines, the available data is limited.  But we have a rather unique opportunity to learn more. (See Swine Flu Vaccine: Watching For Side Effects, here or here.)  Ideally, we might try to evaluate the data objectively, and perhaps free ourselves from an overwhelming amount of emotionally-charged misinformation that pops up in our well-intended flurry of google searches.

What is the Incidence of the Swine Flu?

One important factor in deciding whether to be vaccinated against a disease is its incidence, or likely incidence — what are the odds that you will contract the disease?

The incidence of swine flu is not clear.  Mike Stobbe writes in 1 in 5 Kids Had Flu-Like Illness This Month, TIME, "about 1 in 5 U.S. children had a flu-like illness earlier this month — and most of those cases likely were swine flu, according to a new government health survey. About 7 percent of surveyed adults said they had a flu-like illness, the survey found."  Of course, flu-like symptoms are not synonymous with confirmed swine flu cases.  The error could go either way.  Some people presumed to have swine flu may have a different virus, while some people infected with H1N1 may have few or no symptoms.

Countries are not keeping track of total number of H1N1 cases.  See U.S., Other Nations Stop Counting Flu Cases, TIME: 

U.S. health officials have lost track of how many illnesses and deaths have been caused by the first global flu epidemic in 40 years.  And they did it on purpose.  Government doctors stopped counting swine flu cases in July, when they estimated more than 1 million were infected in this country.

In Swine Flu Infected Millions in First U.S. Wave, CDC Study Finds, Bloomberg, Jason Gale notes that

Swine flu may have infected as many as 5.7 million people in an initial wave that swept across the U.S. earlier this year, researchers at the Centers for Disease Control and Prevention and Harvard School of Public Health said. 

The number of swine flu patients in the U.S. may have been up to 140 times greater than the reported number of confirmed cases, according to a study published in the CDC journal Emerging Infectious Diseases. A model used by the researchers to extrapolate total cases suggests 1.8 million to 5.7 million infections occurred from April to July.

CBS News has also investigated the occurrence of swine flu.  According to CBS, state testing results suggest that H1N1 is not as prevalent as feared.  See for example, Swine Flu Cases Overestimated?:  "If you’ve been diagnosed ‘probable’ or ‘presumed’ 2009 H1N1 or "swine flu" in recent months, you may be surprised to know this: odds are you didn’t have H1N1 flu.  In fact, you probably didn’t have flu at all."

Confusing? Given that estimates may be too high, or too low, the incidence of swine flu is unknown. Similarly, the death rate in the population is not known.  

What are the risks?

In H1N1: Hitting the Young, Riskier for the Old, TIME, Alice Park reports:

researchers are collecting more and more data on the spread of the pandemic flu and getting a clearer picture of its victims — who is most vulnerable to H1N1, how the most severe cases progress and which risk factors tend to contribute to life-threatening disease…

The latest study, published this week in the Journal of the American Medical Association, offers a snapshot of 1,088 H1N1 cases in California that were severe enough to require hospitalization — or resulted in death — between April 23 and Aug. 11 of this year. Experts at the California Department of Public Health, who led the study, say their findings are largely in line with the growing body of data on the worldwide pandemic flu, confirming, for instance, that the 2009 H1N1 flu disproportionately affects younger patients….

While H1N1 infection results in mild or moderate disease in most patients — indeed, the most severe cases account for a small proportion of overall infections — a subset of patients are harder hit, the data show. And in those patients, the disease can often quickly become life-threatening. "The major point of our findings is that there has been a lot of perception that this is a mild disease, and a lot of people may be ambivalent about vaccination," says Dr. Janice Louie, a public-health medical officer at the California Department of Public Health and the study’s lead author. "But for those patients who were hospitalized, 30% required intensive care. This is something that clinicians should be aware of when patients walk into their clinic or office with signs of flu."

Among hospitalized patients in the study, 118 died — an overall 11% fatality rate. Although the rate of hospitalization was highest among infants under 2 months old, the rate of death was highest in patients over age 50; H1N1 was least likely to turn fatal in patients under age 17. Yet with all the focus in the media on the vulnerability of younger patients to infection, the elderly may have been somewhat dangerously overlooked, says Louie. Although older patients may not be at high risk of getting infected in the first place (thanks to their residual immunity to the virus from previous outbreaks of H1N1), their risk of death from the disease may be higher than that of younger patients, primarily because of their higher rates of underlying conditions, such as heart disease, reduced lung function, diabetes and emphysema…

The California data also reveal a potentially new risk factor for H1N1: obesity. Obese individuals were disproportionately represented in the state’s sample of hospitalized cases…

This study suggests that while the swine flu is usually mild or moderate, in the subset of patients with severe disease, the symptoms may rapidly become life-threatening. While the elderly may have some residual protection and are less likely than younger people to be infected with H1N1, once infected, their course is generally worse.

How effective is the H1N1 vaccine? 

Two other factors to consider when deciding whether to get a flu vaccine are the safety and effectiveness of the vaccine.

In the Atlantic’s Does the Vaccine Matter?, Shannon Brownlee and Jeanne Lenzer question the effectiveness of flu vaccines.

But what if everything we think we know about fighting influenza is wrong? What if flu vaccines do not protect people from dying—particularly the elderly, who account for 90 percent of deaths from seasonal flu? And what if the expensive antiviral drugs that the government has stockpiled over the past few years also have little, if any, power to reduce the number of people who die or are hospitalized?…

[The] impact of flu vaccine has been harder to determine. Flu comes and goes with the seasons, and often it does not kill people directly, but rather contributes to death by making the body more susceptible to secondary infections like pneumonia or bronchitis…

[S]tudy after study has found that people who get a flu shot in the fall are about half as likely to die that winter—from any cause—as people who do not. Get your flu shot each year, the literature suggests, and you will dramatically reduce your chance of dying during flu season.

Yet in the view of several vaccine skeptics, this claim is suspicious on its face. Influenza causes only a small minority of all deaths in the U.S., even among senior citizens, and even after adding in the deaths to which flu might have contributed indirectly. When researchers from the National Institute of Allergy and Infectious Diseases included all deaths from illnesses that flu aggravates, like lung disease or chronic heart failure, they found that flu accounts for, at most, 10 percent of winter deaths among the elderly. So how could flu vaccine possibly reduce total deaths by half? Tom Jefferson, a physician based in Rome and the head of the Vaccines Field at the Cochrane Collaboration, a highly respected international network of researchers who appraise medical evidence, says: “For a vaccine to reduce mortality by 50 percent and up to 90 percent in some studies means it has to prevent deaths not just from influenza, but also from falls, fires, heart disease, strokes, and car accidents. That’s not a vaccine, that’s a miracle.”…

Flu researchers have been fooled into thinking vaccine is more effective than the data suggest, in part, says Jefferson, by the imprecision of the statistics. The only way to know if someone has the flu—as opposed to influenza-like illness—is by putting a Q-tip into the patient’s throat or nose and running a test, which simply isn’t done that often. Likewise, nobody really has a handle on how many of the deaths that are blamed on flu were actually caused by a flu virus, because few are confirmed by a laboratory….

In Jefferson’s view, this raises a troubling conundrum: Is vaccine necessary for those in whom it is effective, namely the young and healthy? Conversely, is it effective in those for whom it seems to be necessary, namely the old, the very young, and the infirm? These questions have led to the most controversial aspect of Jefferson’s work: his call for placebo-controlled trials, studies that would randomly give half the test subjects vaccine and the other half a dummy shot, or placebo. Only such large, well-constructed, randomized trials can show with any precision how effective vaccine really is, and for whom.

In the flu-vaccine world, Jefferson’s call for placebo-controlled studies is considered so radical that even some of his fellow skeptics oppose it….

All of which leaves open the question of what people should do when faced with a decision about whether to get themselves and their families vaccinated. There is little immediate danger from getting a seasonal flu shot, aside from a sore arm and mild flu-like symptoms. The safety of the swine flu vaccine remains to be seen. In the absence of better evidence, vaccines and antivirals must be viewed as only partial and uncertain defenses against the flu. And they may be mere talismans. By being afraid to do the proper studies now, we may be condemning ourselves to using treatments based on illusion and faith rather than sound science.

Does the Vaccine Matter? points out problems with vaccine research, highlighting our need to make decisions based on incomplete information. This is not uncommon in medicine. Ultimately, we make choices within the framework of our beliefs, often based more on faith than on science.

Is the vaccine safe?

As millions of people worldwide begin getting the new swine flu shot, public health officials are bracing for rumors about dangerous side effects linked to the vaccine.

To provide context, experts combed hospital databases and population samples in Britain, Canada, Finland, the United States and elsewhere to find daily baseline rates of commonly reported events like Guillain-Barre syndrome, sudden deaths, seizures and abortions…

"People die every day for lots of reasons, but we tend not to think about that when a mass immunization campaign is happening," said Steven Black of Cincinnati Children’s Hospital in Ohio, one of the paper’s authors. "We’re not saying we don’t need to look at vaccine safety, but let’s do it judiciously."

In the end 

After spending weeks reading through available information and realizing what I don’t know still exceeds what I do, I’ll conclude with co-author Terry’s words:

In the world of medicine, safety is a double-edged sword. What if you refrained from having your child vaccinated because of some vague fears about the safety of the vaccine, then watched as your unprotected child contracted swine flu and died of it? The probabilities that this could happen are every bit as relevant as the probabilities that your child may have some side effects from the vaccine, and arguably, quite a bit more relevant. These potential disastrous outcomes associated with declining treatment must be factored in to overall risk.

Consider this: one day you find yourself in a space shuttle awaiting launch, would you rather that the space shuttle was designed, built, and operated by the "establishment" (that is, NASA), with it’s political agendas and various faults and self serving interests, or by a group of amateurs who had done a whole lot of reading and research on the Internet about space shuttles? While nobody can guarantee your safety no matter which of the above two options you pick, I think the best decision is self-evident, and anybody who decides otherwise makes a decision that is not in their own best interests.

We have to entrust our fate; we have to rely upon expert consensus opinion. That is a hugely important source of guidance. If you encourage everybody to read literature and make up their minds, you’ll get a wild spectrum of interpretations and judgments by people who are in no real position to make such judgments generally. This isn’t politics; lives may depend upon this process.  Medicine in general relies heavily upon expert consensus guidance. Professional societies are constantly assembling groups of experts, sometimes very large groups, to meticulously comb through the available data, synthesize interpretations, and make recommendations that are widely promulgated and deployed. That’s because they know that individual physicians could never hope to do as well, as a rule.

So, what exactly are the consensus guidelines? These cannot be just ignored because they represent the medical establishment or because available data is incomplete. If it is incomplete for experts, then it is also incomplete for everybody else, so that is not a useful criteria. As for experts representing the “medical establishment,” I have participated in formulating some of these kinds of expert advisory statements. I can tell you that there is no central dictatory control. They are prepared to print whatever the group as a whole decides and writes, and that’s why they assemble the group in the first place. There is rarely or never any kind of agenda, in terms of the “establishment” foisting something onto the public for some self-serving reason or other. There is no central editorial oversight. The group basically writes whatever the members think is correct. There are usually several leading members of the writing group assembling and writing things, but that’s it.

If you encourage people to just examine whatever information they can find and come to their own conclusions, then you do people a huge disservice. That’s because it is inevitable that they will encounter wrong information, poorly done studies, falsified data, and papers written by people with hidden agendas and ulterior motives. But they will have no way to determine that this is the case, and will tend to give equal weight to articles published in the New England Journal of Medicine by Nobel laureates as articles written in the International Journal of Obscure Tropical Lagoons and Puddles by hucksters, charlatans, shills, frauds, and hired guns.

Whether the information and thoughts compiled here help anyone decide whether or not to get a swine flu vaccine, or the next one when another pandemic strikes, we can only hope.  Jon Stewart, perhaps, says it best, or at least with the most laughs: