On the tuberculosis vaccine -- and why it is not recommended in the US
Last edited Sat Feb 7, 2015, 11:47 AM - Edit history (1)
In the recent vaccine hysteria that seems to have overtaken DU, I have read some misinformation and incomplete information on why it is not generally recommended (but is in specific circumstances) in the US.
First and foremost, the vaccine has relatively low effective rates with relatively short duration of protection.
The most controversial aspect of BCG is the variable efficacy found in different clinical trials, which appears to depend on geography. Trials conducted in the UK have consistently shown a protective effect of 60 to 80%, but those conducted elsewhere have shown no protective effect, and efficacy appears to fall the closer one gets to the equator.[22][23]
http://en.wikipedia.org/wiki/BCG_vaccine
Since 1975, case-control studies using different BCG strains indicated
that vaccine efficacies ranged from zero to 80% (33 ). In young children, the
estimated protective efficacy rates of the vaccine have ranged from 52% to 100% for
prevention of tuberculous meningitis and miliary TB and from 2% to 80% for prevention
of pulmonary TB (34–39 ). Most vaccine studies have been restricted to newborns
and young children; few studies have assessed vaccine efficacy in persons who received
initial vaccination as adults.
The largest community-based controlled trial of BCG vaccination was conducted from 1968 to 1971 in southern India. Although two different vaccine strains that were considered the most potent available were used in
this study, no protective efficacy in either adults or children was demonstrated 5 years after vaccination. These vaccine recipients were re-evaluated 15 years after BCG vaccination, at which time the protective efficacy in persons who had been vaccinated as children was 17%; no protective effect was demonstrated in persons who had been vaccinated as adolescents or adults (39 ).
http://www.cdc.gov/mmwr/PDF/rr/rr4504.PDF
Second, the vaccine may interfere with the skin test for TB.
And third, the rate of infection in the US is very low.
That doesn't mean that there isn't a strategy regarding TB in the US.
In countries where TB infection is high and it has a track record of some effectiveness, it can make sense to vaccinate, and should somebody present with appropriate signs and symptoms, consider them possibly infected and confirm with a more extensive and expensive testing.
In countries where TB infection is low, it makes sense to not vaccinate, and should somebody present with signs and symptoms, rule it out with the quick and inexpensive skin test.
TB Prevention and Control in the United States
The fundamental strategies for the prevention and control of TB include:
· Early detection and treatment of patients who have active TB disease. The most
important strategy for minimizing the risk for M. tuberculosis transmission is the
early detection and effective treatment of persons who have infectious TB (24 ).
· Preventive therapy for infected persons. Identifying and treating persons who
are infected with M. tuberculosis can prevent the progression of latent infection
to active infectious disease (25 ).
http://www.cdc.gov/mmwr/PDF/rr/rr4504.PDF
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