Mike Adams thinks it does. In fact, he’s sure of it. And boy, is he excited. Check out his recent column, and compare that with what the actual study says. First, Adams, with Seasonal flu vaccines increase risk of pandemic H1N1 flu, stunned scientists discover:
The CDC and health authorities were pushing a double-barreled vaccine strategy that demanded people get both a seasonal flu shot as well as an H1N1 pandemic flu shot. Those who questioned the sensibility of vaccines for fighting the flu were attacked as "baby killers" for not kow-towing to the vaccine mythology that drives Big Pharma's profits to record profits nearly every flu season.
Care to guess what the study found? In short, it found that people who received the seasonal flu vaccine shot in 2008 were up to 274% more likely to be infected by H1N1 swine flu than those who skipped the season flu shots.
[Bold in original.]
Note that the CDC recommended getting both the seasonal and H1N1 vaccines. Also note that 274% figure that Adams quotes.
What did this study do, and what does it say? The study is titled Does Seasonal Influenza Vaccination Increase the Risk of Illness with the 2009 A/H1N1 Pandemic Virus? First, you’ll note it starts “Does..” and ends with a question mark. Compare that with Adams’s “…vaccines increase risk…” and no question about it. Adams seems to be a lot more sure than the people who published the actual study. What did they do in this study? Well, they took patients who presented with influenza-like illness at a network of Canadian doctors, and tested them for H1N1 and seasonal influenza. They also determined if the patients had been vaccinated against the seasonal flu. They used this information to compare vaccination status among influenza-positive (both seasonal and H1N1) patients with influenza-negative controls. What did they find?
… receipt of [the seasonal flu vaccine] in the previous season (autumn 2008) appeared to increase the risk of pH1N1 illness by 1.03- to 2.74-fold, even after adjustment for comorbidities, age, and geography . The investigators were prudent and conducted multiple sensitivity analyses to attempt to explain their perplexing findings. Importantly, [the seasonal flu vaccine] remained protective against seasonal influenza viruses circulating in April through May 2009, with an effectiveness estimated at 56% (41%–67%) [My bold.]
Note, they reported that the increased risk was 1.03 to 2.74 fold. Now, I suppose Adams is technically correct in saying the increased risk was “up to 274%” as high, since the phrase “up to” includes the figure zero. Technically correct, but intellectually dishonest. (I guess "more than 1.03 times the risk" wouldn't have sounded so scary.) Also, note that the seasonal vaccine was 56% effective against the seasonal flu – a tidbit that Adams somehow managed to overlook. More importantly, note that the study did not show the merits of getting both a seasonal flu shot as well as an H1N1 pandemic flu shot (compared with no vaccine at all) as Adams himself admits was the CDC’s recommendation. (Presumably they didn’t do this because the H1N1 vaccine wasn’t widely available at the time.)
Still, this did seem (as far as I can tell) to be a decent study, and its results certainly warrant further investigation into this phenomenon. Does this study prove that the seasonal flu vaccine increases the risk of getting H1N1, as Adams thinks? Well, not really. From the report, again:
Given the uncertainty associated with observational studies, we believe it would be premature to conclude that TIV increased the risk of 2009 pandemic illness, especially in light of six other contemporaneous observational studies in civilian populations that have produced highly conflicting results (see Table 1 for details on study design, population sampled, and results) –. We note the large spread of vaccine effectiveness estimates in those studies; indeed, four of the studies set in the US and Australia did not show any association –, whereas two Mexican studies suggested a protective effect of 35%–73% ,. The most recent Canadian study in this issue of PLoS Medicine  is clearly at odds with these results, with an estimated average negative effectiveness of −68% based on their Sentinel system. Only one study, set in the US military population, potentially corroborated the findings of the Canadian study .
So there are numerous other studies, many of which show no difference, and two that actually show the seasonal vaccine reduces the risk of getting H1N1. Nothing wrong with that – real world studies are not always as clear cut as we would like, which is why science requires replication, especially where the results are hard to explain or surprising, based on current knowledge. Strange that Adams didn’t notice that bit, though. Well, it did come nearer the end of the paper - perhaps Adams got so excited by the first part that he didn’t finish reading.
To summarize Adam’s technique, he:
- Cherry picks a study that has results he likes, and ignores at least six other studies (that were even reported in the actual paper he cited) that report different results
- Exaggerates the risk - “1.03 to to 2.74” increased risk becomes “up to 274%”
- Ignores the fact that the seasonal vaccine is 56% effective against seasonal flu anyway
- Ignores the fact that the CDC recommendation is to get both the seasonal and the H1N1 vaccine – something that was not covered by this study. (And presumably the H1N1 will be included in next season’s seasonal fu vaccine.)
- Jumps from all of this to state that therefore “vaccines are a medical scam, folks! A Big Pharma hoax,” and that the real solution to protect you against the flu is vitamin D. Seriously.
Adams will quote a scientific study if it supports his point of view (even if it doesn’t, really), but then he rails against the rest of science that doesn’t. That’s what makes him a crank. The truth is, this is an interesting but inconclusive study that should probably be investigated further. Possibly there is some reason that the seasonal vaccine could make people more susceptible to the H1N1 virus. If so, real scientists would like to find out what it is - although it is almost certainly not that the flu vaccine "weakens the immune system" as Adams claims, but some other reason. More likely (given the numerous confounding studies), there is no real effect here. Either way, it will be real scientists doing real science, not cranks like Mike Adams, who will come up with the actual answer. And you are almost certainly going to be better off getting both seasonal and H1N1 vaccines, than getting neither.
Effect Measure has a good post on this subject this morning, Did getting vaccinated for seasonal flu up the risk of pandemic flu infection? They conclude, like me, maybe, but you’re still better off getting the flu vaccine especially as H1N1 will be a component of the next seasonal vaccine strain.