Thursday, 1 November 2012

Flu Season - Vaccine or Vitamin D?

Flu Season – Vaccine or Vitamin D?

With flu season getting closer we are starting to hear the advertisements advising everyone to get a flu shot.  Medical journals are calling for mandatory flu shots for all health care workers.  I have two questions, 1) are flu shots effective? 2) Is there any better way to protect against influenza? 

Most people assume that flu vaccines are effective but a 2010 Cochrane Collaboration review suggests otherwise.  This description of the Cochrane Collaboration is taken from their website.

 “The Cochrane Collaboration is an international network of more than 28,000 dedicated people from over 100 countries. We work together to help health care providers, policy-makers, patients, their advocates and carers, make well-informed decisions about health care, by preparing, updating, and promoting the accessibility of Cochrane Reviews  

The objective of the 2010 review was to “Identify, retrieve and assess all studies evaluating the effects of vaccines against influenza in healthy adults”    The summary explains some of the limitations of flu Vaccines.

“Over 200 viruses cause influenza and influenza-like illness which produce the same symptoms.....At best, vaccines might be effective against only influenza A and B, which represent about 10% of all circulating viruses.  Each year, the World Health Organisation recommends which viral strains should be included in vaccinations for the forthcoming season”

It is impossible to predict which viral strains we are going to be exposed to in the upcoming season.  Of the possible 200 viruses most flu shots will only offer some protection from 3 virus strains.  It is relatively uncommon for the strains in the vaccine to match the strains we are exposed to.  When they do not match, 2% of unvaccinated people develop influenza symptoms compared to 1% of vaccinated people.  When they do match, the numbers are 4% for unvaccinated people versus 1% for vaccinated.  There is a small decrease in the number of people developing influenza symptoms when vaccinated but the summary noted:

“Vaccine use did not affect the number of people hospitalised or working days lost but caused one case of Guillian-Barre syndrome (a major neurological condition leading to paralysis) for every one million vaccinations”   In their conclusion they stated “There is no evidence that they (influenza vaccines) affect complications, such as pneumonia, or transmission”. 

Another review done at the University of Calgary that looked at vaccinations in health care workers who worked with the elderly and found “there is no evidence that vaccinating HCWs (health care workers) prevents influenza in elderly residents in LTCFs (long term care facilities).”

Almost half the trials studied were funded by the vaccine industry.  “ Studies funded from the public sources were significantly less likely to report conclusions favourable to the vaccines.  The review showed that reliable evidence on influenza vaccines is thin but there is evidence of widespread manipulation of conclusions and spurious notoriety of the studies.”  Industry studies were not only more likely to be positive but they were “published in more prestigious journals and cited more than other studies independently from methodological quality and size”

Proponents of flu vaccines will point to the hundreds of Observational studies that have reported an approximate 50% reduction in all cause deaths in vaccinated seniors compared to unvaccinated seniors.  This topic was reviewed in this paper.  “ a 50% vaccine effectiveness (VE) against death from any cause sounds too good to be true, if only because influenza is related to an average of only about 5% of all senior deaths during winter and the observed impact occurring prior to the season”  

A 50% reduction in deaths when only 5% of deaths are related to influenza indicates possible selection bias in the studies.  When the researches went through the cohort studies showing a 50% VE, they found that “the greatest difference in mortality rates among vaccinated and unvaccinated seniors in the HMO database studies turned out to occur in the months before the influenza epidemic period, and strategies commonly used for adjustment of bias in cohort studies were counter-productive”  The fact that the studies show that the vaccine prevented more deaths prior to flu season than it did in flu season demonstrates vaccination selection bias. When they dug further they found the probable cause of the confounding.  There is a subset of frail and terminally ill seniors who are less likely to become vaccinated because of their deteriorating health.  These unvaccinated seniors have a much higher mortality rate which confounds the results. 

They also noted a 2003 CDC study  that found that while vaccination coverage in the 80’s and 90’s quadrupled, influenza-related mortality rates increased at the same time.  This is an observational study, so it can find correlations, not cause and effect, but it is still interesting to note that mortality rates increased along with vaccination rates.  

After searching through all the scientific data these researchers could only find one Randomised Controlled trial that showed a small improvement in influenza symptoms but no significant  effect on hospital days, working days, complications or transmission.  They were not able to draw and conclusions from the other cohort studies due to the general low quality of the studies or presence of biases.  Randomised Controlled Trials need to be done to demonstrate improvements in outcomes like hospitalisation's, work days missed, complications and transmission.  With the science available today it is hard to make a recommendation on voluntary vaccinations and is even more difficult to reconcile mandatory vaccinations.  

Some of the reasons people may not want to take unnecessary vaccines is because of the ingredients in the vaccines.  Multi dose influenza vaccines usually contain thimerosol which is a mercury containing compound.  They may also contain aluminum oxide and formaldehyde.  We are told that they are in very small amounts that are safe. Macrophagic myofasciitis (MMF) has been linked to aluminum oxide used as an adjuvant in some vaccines.  The question is, do we want any amount of a neurotoxic metal injected into our bodies if it not going to result in meaningful benefits?  These adjuvants are used to stimulate the immune system to provoke a larger response to the vaccine.  Could these repeated artificial stimulation's impacting allergies and autoimmunity?  We don’t know the answers to these questions. 

A simple and maybe even more effective way of dealing with flu season may be to make sure you have adequate levels of vitamin D.  This 2010 randomised controlled study showed that children taking vitamin D supplements were 42% less likely to get the flu.  Vitamin D’s effects on the innate immune system appears to “both enhance the local capacity of the epithelium to produce endogenous antibiotics and – at the same time – dampen certain arms of the adaptive immune response, especially those responsible for the signs and symptoms of acute inflammation, such as the cytokine storms operative when influenza kills quickly.”

A 2006 paper appearing in the journal Epidemiology and Infection made the following observations.

“1. Why the flu predictably occurs in the months following the winter solstice, when vitamin D levels are at their lowest,

2. Why it disappears in the months following the summer solstice,

3. Why influenza is more common in the tropics during the rainy season,

4. Why the cold and rainy weather associated with El Nino Southern Oscillation (ENSO), which drives people indoors and lowers vitamin D blood levels, is associated with influenza,

5. Why the incidence of influenza is inversely correlated with outdoor temperatures,

6. Why children exposed to sunlight are less likely to get colds,

7. Why cod liver oil (which contains vitamin D) reduces the incidence of viral respiratory infections,

8. Why Russian scientists found that vitamin D-producing UVB lamps reduced colds and flu in schoolchildren and factory workers,

9. Why Russian scientists found that volunteers, deliberately infected with a weakened flu virus - first in the summer and then again in the winter - show significantly different clinical courses in the different seasons,

10. Why the elderly who live in countries with high vitamin D consumption, like Norway, are less likely to die in the winter,

11. Why children with vitamin D deficiency and rickets suffer from frequent respiratory infections,

12. Why an observant physician (Rehman), who gave high doses of vitamin D to children who were constantly sick from colds and the flu, found the treated children were suddenly free from infection,

13. Why the elderly are so much more likely to die from heart attacks in the winter rather than in the summer,

14. Why African Americans, with their low vitamin D blood levels, are more likely to die from influenza and pneumonia than Whites are.”

These are observations so they cannot prove cause and effect but they point to the need for Randomised Controlled Trials to be done on the health benefits of Adequate vitamin D levels.
Serum Vitamin D levels can be tested but they are not covered by BC Medical.  It is my opinion that millions of dollars would be saved in health care costs if BC Medical paid for Vitamin D tests and everyone had adequate levels of vitamin D.  If you want to get tested ask your doctor for a  25-hydroxyvitamin D, or 25(OH)D.  There is some debate about what the ideal level of serum vitamin D is but a level of around 50 nmol/L seems to be a common range with most experts.

Most people today need to supplement with Vitamin D3.  It is very hard to get from our diet, historically we made our own Vitamin D with exposure to the sun. Most people work indoors and do not get adequate sun exposure.  When we are in the sun we are told to cover up and put on sunscreen, which blocks the production of vitamin D.  Sun burns are definitely dangerous, but responsible sunbathing, 10-15 min/day without sunscreen, can be a very healthy way to get your vitamin D.  Even if you do get adequate sun exposure in the summer the sun is not high enough in the winter to get adequate vitamin D if you live in Canada, so some supplementation is recommended.  The vitamin D Council states that it is safe to supplement with up to 10 000 IU of vitamin D3/day and recommends adults take 5 000 IU/day.

Reducing systematic inflammation and having adequate vitamin D levels, along with its cofactors Vitamin A and K2, strengthens your immune system. This not only reduces your risk from influenza, but may also have to following benefits:
-protect the common cold
-help prevent and in some cases treat cancer
-increase bone health
-increase dental health
-protect against cardiovascular disease

With all the benefits of Vitamin D I see no reason not to supplement during the winter months.  A more prudent method of dealing with influenza in health care workers might be to test Vitamin D levels and supply supplementation.   This applies if you choose to get the flu shot or not.  Eating a diet that does not cause inflammation and getting enough sleep along with maintaining adequate vitamin D levels will help you make it through flu season.

1 comment: