Sunday, 11 August 2013

BCG Incidence & Mortality Rate in Malaysia 2013

Let's talk about the effectiveness of the BCG vaccine for Tuberculosis disease. It is administered to newborns & a 2nd dose is administered at 7 years old (if no scar) based on the current vaccine schedule.

Below are 3 tables taken from the Health Facts 2013 file released by the Ministry of Health, Malaysia. I was searching for the Tuberculosis incidence rate in Malaysia, and surprisingly it isn't listed inside the vaccine preventable diseases table. I found it inside the Other Infectious Diseases table.

Table 1: Vaccine Preventable Diseases - no mention of Tuberculosis [1]

Table 2: Other Infectious Diseases[1]

Table 3: Childhood Immunisation Coverage, 2012 [1]


The highest incidence rate in Table 2 is 117.66 (per 100,000 population) for Hand, Foot & Mouth Disease - there is no vaccine available at the moment for this disease. This is followed by Tuberculosis with 77.41 (per 100,000 population).
.
BCG Immunisation Coverage of Infants: 98.72%
Incidence rate (per 100,000 population): 77.41
Mortality rate (per 100,000 population): 4.82

Hmm, this BCG vaccine doesn't seem too effective? Perhaps because the tuberculosis strain in the vaccine is sourced from a cow and might not provide immunity for human-to-human transmission?
BCG Vaccine for percutaneous use, is an attenuated, live culture preparation of the Bacillus of Calmette and Guerin (BCG) strain of Mycobacterium bovis. [2]
What is Mycobacterium bovis?
Mycobacterium bovis is spread from cow-to-cow by inhalation of the organism in aerosolized droplets. When people are infected by inhalation of the organism shed from the airways of infected cattle, they can develop classic pulmonary Tuberculosis similar to Mycobacterium tuberculosis infection.
People can then shed the organism from their airways back to other cattle. However, person-to-person transmission of Mycobacterium bovis is considered to be quite rare. [3, 4]
Possible BCG vaccine side effects: “Flu-like” syndrome, fever, anorexia, myalgia, and neuralgia, disseminated BCG infection, moderate axillary or cervical lymphadenopathy and induration and subsequent pustule formation at the injection site; ulceration at the vaccination site, regional suppurative lymphadenitis with draining sinuses, and caseous lesions or purulent draining at the puncture site.[6]

One of the reasons that is often mentioned for BCG vaccination is due to the number of foreigners in Malaysia. Example of countries that:

  • DO NOT have BCG vaccine on their schedule: Australia, Finland, Germany, Netherlands, USA, UK.
  • DO have BCG vaccine on their schedule: China, Indonesia, Vietnam, Thailand, Myanmar, Philippines [5]


Food for thought: Which foreigner are we worried about and is it worth the risk of vaccine side effect along with the ineffectiveness of this vaccine?



References
  1. Health Facts 2013 from Ministry of Health, Malaysia http://moh.gov.my/images/gallery/publications/HEALTH%20FACTS%202013.pdf
  2. BCG vaccine http://www.drugs.com/pro/bcg-vaccine.html
  3. Mycobacterium bovis http://www.vetmed.wisc.edu/pbs/zoonoses/Tuberculosis/mbovis.html
  4. Low risk of infection with Mycobacterium bovis in the UK – 1 July 2013 https://www.gov.uk/government/news/low-risk-of-infection-with-mycobacterium-bovis-in-the-uk-1-july-2013
  5. The BCG World Atlas http://www.bcgatlas.org/
  6. BCG vaccine insert (Merck) http://www.merck.com/product/usa/pi_circulars/b/bcg/bcg_pi.pdf

1 comment:

  1. Hi, according to WHO, BCG vaccine has a documented protective effect against meningitis and disseminated TB in children. BCG vaccine actually protect against SEVERE form of TB.

    Mycobacterium tuberculosis have various strains which is not all be covered by BCG vaccine. And, I believe that the high rate of incidence of Tuberculosis is referred to Pulmonary TB.

    Since we will be protected(although not 100%) against severe disease that has high mortality rate, why should we refuse for bcg vaccine? Just my 2 cents.

    ReplyDelete