Swine flu vaccine effectiveness

How effective is the swine flu vaccine? How confident are you that it will protect you and your family?  Should your children get it?


The medical community is split on this issue.  In this article I analyze the data presented by both sides – and let you decide whether it makes sense for you and your family to get vaccinated.

What are the doctors saying?

Dr. Blaylock is a neurosurgeon and educator, known for his position against vaccination. He points out that vaccine is practically useless for protection from influenza 2.  He references a number of studies from the Cochrane Database of Systematic Reviews, dated from 2004 to 2009.

Doctors from the Public Health Agency of Canada (PHAC) officially stated in October 2009: “Vaccination is recognized as the cornerstone for preventing or attenuating influenza for those at high risk of serious illness or death from influenza infection and related complications."1

They referenced the studies from the very same Cochrane Database of Systematic Reviews in their assessment of the vaccine’s efficacy.

How effective is the swine flu vaccine?

According to Dr. Blaylock, vaccination reduced the risk of influenza as follows:

  • In babies under two years – by 0%  (non-significant statistically, no better than placebo)
  • In healthy children over 2 years – by 33%
  • In healthy adults – by 6%
  • In the elderly – by 0% (non-significant statistically).

Public health officials cite 80% efficacy of the vaccine and highly recommend vaccination, especially to children.

Who should we believe?

Let’s compare notes on vaccination of children over 2 years of age:

"Do flu shots work?
In a review of more than 51 studies involving more than  294,000 children it was found there was “no evidence that injecting children 6-24 months of age with a flu shot was any more effective than placebo. In children over 2 yrs, it was only effective 33% of the time in preventing the flu. Reference: Vaccines for preventing influenza in healthy  children.  The Cochrane Database of Systematic Reviews. 2 (2008). "

Dr. Russell Blaylock

"Immunization of healthy persons aged 2 to 64 years.
Individuals in this age group are encouraged to receive the vaccine, even if they are not in one of the aforementioned priority groups. Systematic reviews of randomized controlled trials in healthy children and adults show that inactivated influenza vaccine is about 70% to 90% effective in preventing laboratory-confirmed influenza infection (29-31;72;73). A recent meta-analysis of randomized-controlled-trials since 1966 found a vaccine efficacy in young adults of 80% ... against laboratory-confirmed influenza when measured during select seasons of vaccine match and 50% ... during select seasons of vaccine mismatch to circulating virus.(73)

Public Health Agency of Canada

Why such a difference in the opinions of two respected sources?

To answer this question, I went directly to the source - The Cochrane Database for Systematic Reviews. It’s open to the public, and can be accessed for free without subscription.

Dr. Blaylock referenced a summary study in his analysis of vaccine efficacy and effectiveness. It comprised 51 studies with 294,159 observations, of which 16 were randomized controlled studies and 18 were cohort studies.

The studies referenced by the Public Health Agency of Canada were individual studies.

There is another difference: Dr. Blaylock speaks of the effectiveness of the vaccine, while the PHAC speaks of efficacy.

Aren’t these words synonyms  - meaning the power to produce an effect?

In spoken English, yes. However, in medical terms, there is a fundamental difference.

Both sources are truthful and refer to the real results of the studies - the fundamental difference is:

Efficacy vs effectiveness

From the US National Library of medicine:

“In the clinical development of a vaccine, an efficacy study asks the question, ‘Does the vaccine work?’ In contrast, an effectiveness study asks the question ‘Does vaccination help people?’.
In general, vaccine development proceeds from a study of immunogenicity to a randomized controlled trial that determines vaccine efficacy under ideal conditions”.

Pasteur Mérieux MSD

In other words, an efficacy of 80% cited by the PHAC shows that in the controlled, carefully selected group of healthy children over two years, the vaccine worked 80 times out of 100. Think of it as the maximum protection that the vaccine is capable of providing under ideal conditions. No wonder they recommend vaccination! PHAC’s mission is "to help reduce pressures on the health-care system" - every  1% reduction in swine flu pandemic levels and related hospitalization counts.

Life corrects these numbers. Some children have underlying medical conditions, some have allergies, some could be already infected with the virus – few children are completely healthy these days. Some just got another vaccine that may interact with the swine flu vaccine. These and other individual factors will reduce the effect of the vaccine.

Data collected over the period of time from the large number of people shows effectiveness of the vaccine.

Effectiveness is a better indicator when dealing with larger populations, which we are.

In public health practice, effectiveness, not efficacy, provides a better estimate of the chances that this vaccine will help your children.

"In future years, effectiveness studies, some of them using large administrative databases, will become increasingly important features of vaccine development and the formulation of public policy for immunization."

Pasteur Mérieux MSD

So how effective is the swine flu vaccine for children older than 2 years ?

The authors of the study cited by Dr. Blaylock make this conclusion:

"There was a marked difference between vaccine efficacy and effectiveness….From RCTs (randomized controlled studies), live vaccines showed an efficacy of 82% …and an effectiveness of 33% … in children older than two compared with placebo or no intervention. Inactivated vaccines had a lower efficacy of 59% … than live vaccines but similar effectiveness: 36%..."

Note that the swine flu vaccine is not a live vaccine; it is inactivated. Also note that the studies above are from previous years’ vaccines, and do not indicate that the swine flu vaccine will be as effective.

Based on the data available, there may be one in three chances (33-36%) that swine flu vaccine will protect your children.

How about children under two?

Authors of the summary study conclude:

"In children under two, the efficacy of inactivated vaccine was similar to placebo.”

"It was surprising to find only one study of inactivated vaccine in children under two years, given current recommendations to vaccinate healthy children from six months old in the USA and Canada"

"No safety comparisons could be carried out, emphasizing the need for standardization of methods and presentation of vaccine safety data in future studies.. If immunisation in children is to be recommended as a public health policy, large-scale studies assessing important outcomes and directly comparing vaccine types are urgently required."

In other words, in the only available controlled study, the vaccine showed no better protection than placebo for children under two.

PHAC admitted  the lack of needed study of the vaccination for children under two , and still supported the recommendation of the National Advisory Committee on Immunization (NACI) that children under two be vaccinated:  

“Healthy children 6 to 23 months of age. Children in this age group are at increased risk of influenza-associated hospitalization compared with healthy older children and young adults. Hospitalization is most frequent in those <2 years of age… NACI recognizes that both the number of studies and the number of participants in trials of influenza vaccine in children of this age are limited, that there are unanswered questions (for example, the uncertain efficacy of vaccine … ).  NACI strongly encourages further research regarding these issues. However, on the basis of existing data indicating a high rate of influenza-associated hospitalization in healthy children <24 months, NACI recommends the inclusion of children 6 to 23 months of age among high-priority recipients of influenza vaccine.”1

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I constantly monitor scientific publications on swine flu along with healthy foods topics. In the next articles, I will post :

  • analysis of effectiveness of the flu vaccine in healthy adults
  • dangers of the swine flu vaccine
  • immune-boosting foods and supplements.

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1. Official Statement of the Public Health Agency of Canada
2. The link to "http://www.cochrane.org/reviews/en/ab004879.html", "Study: Vaccines for preventing influenza in healthy children", became unavailable in May 2012
3. Efficacy vs effectiveness


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