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Vaccine Misconception of the day

June 7, 2010 Leave a comment

I’m thinking of making this a regular feature. I will list general misconceptions that people hold in regards to vaccines and hopefully that’ll prompt people to research more carefully. Here goes today’s Vaccine Misconception.

“The consequences of being vaccinated with side effects and something going wrong are greater than the risk of him catching something and allowing his immune system to fight it naturally,” she said.

Fletcher’s Mom

Skepdude says – To Fletcher’s mom: I have a 3 year-old. I made sure she got all her vaccinations as recommended by the CDC. She has never had any adverse effects to any of the vaccines. So there, I have one anecdote for your anecdote. It’s a tie. Where does that leave us now? It should leave us with the science, and the science says that your fears are misplaced. Any side effects vaccines cause is greatly outweighed by the harm they prevent. You should not be so willing to have your child catch diseases for his immune system to “fight it naturally”. It’s a fight he may end up loosing, the same way Keira Skaife, Callie Grace, or Dana McCaffery did.

Think of the vaccines as swimming aids. Would you put those on your child to help him learn how to swim, even though they may cause him a bit of skin irritation, or would you throw him overboard and let him learn how to swim “naturally”? If you go the “natural” way, he may learn how to swim and survive, but the likelihood of him drowning in the process goes way up. The risks of vaccines vs. the risks from the disease are like the risk of skin irritation vs. the risk of drowning in my analogy. I suggest you redo your research and reconsider your decision.

Pneumonia vaccine ineffective?

June 7, 2010 2 comments

Pneumonia vaccine ineffective against repeat infections: study” screams the headline. The article goes on to clarify that a study just published seems to suggest that the pneumococcal vaccines in use in Canada do not seem to perform any better than no vaccine. How is that possible? Well, so far as I can tell, it isn’t, and this seems to be another case of dubious reporting by the journalists, and careless conclusions by paper authors.

I could not get my hands on a copy of the full published study the article refers to, although I will probably be able to in the near future. In the mean time, all I can go on is the abstract which can be found at PubMed or at Chicago Journals. Let us examine exactly what this study seems to suggest, based on the publicly available abstract.

Background.There is debate surrounding the effectiveness of the 23‐valent pneumococcal polysaccharide vaccine (PPV). We determined whether PPV was associated with reduced mortality or additional hospitalization for vaccine‐preventable infections in patients previously hospitalized for community‐acquired pneumonia (CAP).

Ok, so first thing to keep in mind: they only studied people who got pneumonia. This is not a study comparing vaccinated vs. unvaccinated, and seeing if there is any protection offered by the vaccine in the form of reduced infection rates. This is a study consisted of only people who got sick, breaking those down into two groups and seeing how each group fared.

Now, it is an accepted fact that no vaccine is 100% effective, meaning that no vaccine will prevent the disease on all people who receive it. For one reason or another, some people get no benefit from any given vaccine. Those people will get sick from the disease, regardless of their vaccination status.  By definition, if you are gathering together people who are sick in the hospital, you are already limiting yourself to only that subset of the vaccinated population for whom the vaccine has already failed. So from that point alone, this is like saying “Well let me find all the people for whom the vaccine failed & let me measure how effective the vaccine was for them“. Just to make a comparison, this sounds kind of like saying “let me find out which team lost, and see how likely they are to have won!“.

Results.A total of 2950 patients were followed up for a median of 3.8 years. The mean patient age was 68 years; 52% were male. One‐third (n=956) received PPV: 667 (70%) before and 289 (30%) during hospitalization. After discharge, 1404 patients (48%) died, 504 (17%) were admitted with vaccine‐preventable infections, and 1626 (55%) reached the composite outcome of death or infection. PPV was not associated with reduced risk of the composite outcome (589 [62%] vs 1037 [52%] for those unvaccinated; adjusted hazard ratio [HR], 0.91; 95% confidence interval [CI], 0.79–1.04). Results were not altered in sensitivity analyses using propensity scores (adjusted HR, 0.91; 95% CI, 0.79–1.04), restricting the sample to patients 65 years or older (adjusted HR, 0.90; 95% CI, 0.77–1.04), or considering only those who received PPV at discharge (adjusted HR, 0.84; 95% CI, 0.71–1.00).

Second point to keep in mind; the mean patient age was 68 years. The study is itself limited to only “adults at high risk for pneumonia”. So at best, the results of this study might hold for adults, average 68 years old, for whom the vaccine has already failed to offer immune protection. That is quite a small subset of all people who get the vaccine. The question to ask ourselves is: how reliable are such results and how can they be applied to the total vaccinated population?

Conclusions.One‐half of patients discharged from the hospital after pneumonia die or are subsequently hospitalized with a vaccine‐preventable infection within 5 years. PPV was not associated with a reduced risk of death or hospitalization. Better pneumococcal vaccination strategies are urgently needed.

And this is the careless conclusions that I was referring to: “Better pneumococcal vaccination strategies are urgently needed.” Better than what? That is the confusing part. If you choose to only look at the people for whom the vaccine has already failed, what really do you expect the results to be? If the person got sick, the vaccine failed to protect them. If the vaccine failed, wouldn’t we expect both failed-vaccinated and unvaccinated groups to show the same pattern? What insight can one gain by looking at the failed vaccine group? Confirmation that a vaccine that failed to prevent the disease in the person, also fails to reduce mortality rates from the disease? So this study possibly tells us that in people over 68, when the pneumococcal vaccine fails, it fails completely. Hmm, ok, isn’t that kind of to be expected anyway?

How can these results support the conclusion that better pneumococcal vaccination strategies are urgently needed though? The study did not examine pneumococcal vaccine efficacy, like this one properly did, by comparing vaccinated vs. placebo shots and checking out infection and morbidity rates.  The only question this study aimed to answer is this: When the vaccine fails to build immunity, does it also fail to protect from death? And the answer, unsurprisingly, is coming back to be yes.

Maybe some vaccines reduce death rates from the disease even if they fail to build immunity against the disease. I guess that is plausible; I don’t know enough to say. However, it appears to me that, the way this study was designed, the way the groups were chosen, leaves a lot to be desired and seems to be set up so as to provide only one possible answer. This study seems better equipped to figure out the mortality rate from pneumococcal than the efficacy of the pneumococcal vaccine. The authors should be more careful with their conclusions and keep in mind the limits of their design; they should be the first ones to acknowledge that their study cannot be generalized to the whole vaccinated population. Yet, somehow they fail to do that and instead make unwarranted conclusions about improving vaccination strategies. That coupled with journalists looking for sensational headlines unfortunately has the effect of sending a message to the public that is not supported by the science. And that is sad; sad and dangerous.

REMINDER: These comments should be held as temporary until I get my hands on the full PDF. That will either verify that my interpretation of the abstract is correct, or I will have to come back and modify my interpretation.

Categories: Efficacy, Pneumococcal Tags:

12 children die during bad luck ceremony

June 7, 2010 Leave a comment

READ THE FULL STORY AT ABC

Twelve Indonesian children have died after a suspension bridge collapsed as they were taking part in a traditional ceremony to dispel bad luck, a local official said.

The accident took place in a remote village in Aceh.

“There were about 37 kids gathered together on a wire-cable suspension bridge when it collapsed and they fell into a river,” district chief Ibnu Hasyim said.

Twenty-five children were rescued with minor injuries but 12 others – all below the age of 12 – were swept away in strong currents.

The children were watching a ritual ceremony to dispel misfortune after a measles outbreak in the area.

READ THE FULL STORY AT ABC

Vacation Break

June 7, 2010 1 comment

Beloved Readers, Skepdude will be taking a much needed vacation break through the beginning of  July.  As I will be spending time in an internet free beach in the Mediterranean (yes, such places still exist), and given that the World Cup will be happening, do not expect many entries from now, through the beginning of July. I know the internet will not be the same without my lovely ramblings, but until then, may I suggest Hulu?

Categories: Uncategorized

Whooping cough cases soar in Marin and state

June 4, 2010 Leave a comment

READ THE FULL ARTICLE AT CONTRACOSTATIMES

Marin County health officials say the number of whooping cough cases reported so far this year is already three times greater than the number of cases reported during all of 2009.

Dr. Anju Goel, Marin deputy public health officer, said 58 cases of whooping cough, a highly contagious respiratory tract infection also known as pertussis, were reported in Marin from Jan. 1 to May 17, compared with just 19 during 2009.

The higher Marin numbers reflect a statewide phenomenon. According to the California Department of Public Health, 346 pertussis cases were reported in California from Jan. 1 to April 30, up from 129 cases during the same period last year.

Statewide, four newborns have died from whooping cough – two in Los Angeles County and two in the Central Valley. State health officials say pertussis cases tend to be cyclical, with a rise in the number of cases every two to five years followed by a decline.

“The last big outbreak of pertussis cases was in 2005,” said Ken August, a state Department of Public Health spokesman. “So we’re concerned we could be in for another tough year.”

In 2005, pertussis killed eight California infants.

Infants, the elderly and those with weakened immune systems are most at risk. According to the Centers for Disease Control and Prevention, more than half of infants less than 1 year old who get the disease must be hospitalized. About one in 10 children with pertussis get pneumonia, and about one in 250 people who become infected develop a brain disorder called encephalopathy. The disease causes an estimated 10 to 20 deaths each year in the United States.

In Marin, the Ross Valley School District’s five campuses in San Anselmo and Fairfax are being hit the hardest.

READ THE FULL ARTICLE AT CONTRACOSTATIMES

CDC releases preliminary data on 2009 H1N1 vaccine and Guillain-Barre Syndrome

June 4, 2010 4 comments

As part of its Morbidity and Mortality Weekly Report (MMWR), the Centers for Disease Control and Prevention (CDC) has released a report titled “Preliminary Results: Surveillance for Guillain-Barré Syndrome After Receipt of Influenza A (H1N1) 2009 Monovalent Vaccine — United States, 2009–2010“.  This publication reports on an analysis of preliminary data, the focus of which was to look for any signs of increased risk of GBS rates among individuals receiving the 2009 monovalent H1N1 vaccine in the United States.

Guillain-Barre Syndrome is a rare neurological disorder (affecting about 1.65 and 1.79  in 100,000)  in which the body’s immune system attacks part of the peripheral nervous system. On some occasions, it has been  identified to be triggered by surgery or vaccination. For example, as has been widely reported, especially by the anti-vaccination crowd, the 1976 influenza A (H1N1) vaccine was associated with a statistically significant increased risk for GBS of over 10 cases per million, and it appears that some vaccines may account for a slight overall increase in GBS risk.

Given the history with the 1976 H1N1 vaccine, the CDC has been closely monitoring the 2009 H1N1 vaccines, through its Emerging Infections Program (EIP) since October 2009.  Preliminary results of this analysis show an excess of 0.8 cases of GBS for 1,000,000 vaccinations, similar to the rate for seasonal influenza vaccines. If this holds up when the full review is released some time in the Fall of 2010, it would mean that the 2009 H1N1 vaccine will be associated with an 8% increase over the expected GBS rate of 1 in 100,000.

To put things in perspective, while the H1N1 vaccine may be associated with less than 1 additional case of GBS per million vaccines, the disease it protects from, H1N1 influenza has been associated with 9.7 deaths per million. According to Wikipedia, 80% of GBS patients recover fully, which means that of the 0.8 additional cases per million vaccination, only about 0.16 will have permanent effects (including paralysis and death). To put this further into perspective, if this association holds, we should expect about 16 cases of additional GBS with permanent side effects, for every 100,000,000 vaccinations. At the same time the death rate from influenza A (H1N1) would be at about 970. And if that is not enough perspective, according to this study, the mortality rate, at least for the period 2000-2004 was at 2.58 %, whereas Wikipedia estimates overall mortality rate to be at around 4%. Using the larger number, the 4% from Wikipedia, if the association holds at the same level, we would expect an additional 3.2 vaccine induced GBS deaths versus 970 influenza H1N1 deaths, per 100 million people.

Even if the H1N1 vaccine is only 50% effective in preventing H1N1 influenza, that’s still  485 saved lives vs. 3.2 additional deaths.  This overwhelmingly shows that vaccinating for influenza A (H1N1) is to be highly preferred vs. not vaccinating, since the chances of any one person dying from influenza would be about 151 times higher than dying from vaccine induced GBS. To put it differently, every person that chooses not to vaccinate for H1N1 out of fear of dying of vaccine induced GBS, is effectively choosing to take a risk of dying from the disease 151 times higher than the one they are afraid of (and this is only at an assumed 50% vaccine efficacy rate)! That is kind of like preferring to jump out of the 10th floor of a building because you’re afraid you may break your leg jumping out of the first floor window.

Vaccine preventable death – Keira Skaife

June 1, 2010 4 comments

Age at death – 2 months

Cause of death – Pertussis (whooping cough)

Vaccination status – Vaccinated, received first dose only a few days before coming down with the disease.

Synopsis – Keira was only two months old when she lost her two-week fight against whooping cough. She had received her first pertussis shot days before coming down with the disease, too soon for the shot to have built up her immune response. It was the first of 3 pertussis shots she was going to receive during the first 6 months of her life. Our hearts and thoughts go out to Keira’s parents; we are very sorry for you terrible loss.

Source

Newspaper article image courtesy of The Second Sight blog.