"In the UK the government Health Authority quotes figures of the measles vaccine as being 90% effective (which means that) 90% of the recipients of the vaccine, produce a certain level of antibodies to the viral agents in the vaccine, 10% have produced no or undetectable levels of antibody. This information has NOT been derived from population studies and as we have already acknowledged, this does NOT indicate what percentage of those people are actually immune, (or, for that matter, how long that apparent immunity lasts). So, to state that the vaccine is 90% effective is somewhat misleading and at any rate inaccurate with regard to a statement of immunity in a real disease situation."--Trevor Gunn BSc
Toscani
L, et al. [Comparison of the efficacy of various strains of mumps vaccine:
a school survey]. Soz Praventivmed. 1996;41(6):341-7. French. PMID: 9027138; UI:
97161702.RESULTS: Raw estimation of vaccine efficacy against mumps was 72.5%. Whereas both
the Urabe and Jeryl-Lynn strains showed a significant efficacy, the Rubini strain didn't
show any significant protective effect. After adjustment by Poisson regressions for the
confounding effect of age, efficacy rates and 95% confidence limits were 75.8% (35.6%,
90.9%) for Urabe; 64.7% (10.6%, 86.0%) for Jeryl-Lynn; and 12.4% (-102%, 62.1%) fur Rubini
Chickenpox vaccine (80%)--"Of 85 study participants who came into contact with the virus through household exposure after being vaccinated, 18 developed the disease"--Reuters Limited
As many as 50% of people over the age of 60 don't respond to licensed hepatitis B vaccines," Dr. Poland told Reuters Health. "It is also a problem in HIV patients, diabetics, immunosuppressed patients, obese individuals, dialysis patients and smokers." When "you put all these groups together you realize that there are a fair number of people who are not protected against hepatitis B," he noted
Efficacy stats by a vaccinator, David Elliman:
Efficacy of vaccines |
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Many parents point out that some infectious diseases were on the decline before the relevant vaccine was introduced and so how can it be certain that immunisation has had any effect. Before a vaccine is introduced it undergoes trials to ensure it has a reasonable efficacy. Trials of all the routine childhood vaccines in use today have shown them to be highly efficacious (box 2). Before the introduction of whooping cough vaccine, studies showed that it provided a high degree of protection.11 More recently trials have confirmed its high efficacy. 12 13 Although protection against infection is not 100%, the symptoms and signs of the disease in a child who has completed a course of three doses of the whole cell vaccine used in the United Kingdom are almost always milder than those in an unimmunised child.
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Several disease outbreaks have occurred in populations that were unimmunised but otherwise healthyfor example, in the past 25 years two outbreaks of paralytic polio occurred in an unimmunised religious community in the Netherlands.15 In neither case did the disease spread outside the community. The Amish and other religious groups that eschew immunisation have also had a disproportionately large number of cases of whooping cough, measles, and congenital rubella.16-18
Some outbreaks of diseases, particularly measles and whooping cough, have taken place in highly immunised populations. When a large percentage of those affected have been immunised it is often inferred as proof that the vaccine is not efficacious. Even if a large percentage of the general population is immunised, unless the vaccine is 100% effective a large proportion of infected children will have been immunised. The numbers of immunised and non-immunised children infected in these outbreaks invariably shows that these vaccines have a high efficacyfor example, in an outbreak of measles in Quebec City in 1989 of 62 siblings of children with measles who developed measles themselves, 41 (66%) were immunised.19 This might suggest that the vaccine was not effective, but of 17 unvaccinated siblings all (100%) developed measles, whereas only 41 of 441 (9%) vaccinated siblings did so. This gives a vaccine efficacy of 91%. If none of the children had been vaccinated a further 400 cases would have occurred.
Importantly, not all preparations of a vaccine are the same. Although little
variation occurs in measles vaccines used in the developed world, the efficacy
of different pertussis vaccines varies enormously. Recent trials showed that
one variety of pertussis vaccine had an efficacy of 35%-40%, whereas the two
types used in the United Kingdom had over 90% efficacy. 12
13 The Jeryl Lynn mumps vaccine used in the
United Kingdom has an efficacy of over 90%, whereas a recent study shows the
Rubini strain to offer no protection.14