Re: “Antivaccine Lobby” replies to the BMJ
1 February 2013
We offer our comments to this and a blog that has appeared on 21st Dec. 2012 and Jan. 2013.Pentavalent Vaccine – Safety
We read with interest and some anguish Jacob Puliyel’s blog on 21st Dec 2012 and comments thereafter. Hypothecated advocacy raising concerns about pentavalent vaccine in Kerala, India, seems to be based on some statistics and scientific evidence which needs to be revisited and rectified. We also read with interest article in BMJ 2013, 346:1516 on “US Vaccination Schedule is Safe & Effective ..” and feel that India should not get deterred by comments on incidence of Hib disease, safety of vaccines, but, continue its vaccination policy.
For any vaccine to be introduced in the community, we need to asses these factors –
a) Disease burden in the population.
b) Safety and efficacy of the vaccine.
c) Cost effectiveness and sustainability.
d) Logistic and administrative issues.
a) When we analyse the burden of Hib disease in India, one must consider both Hib meningitis and pneumonia. Study by Minz S et al1 on incidence of Hib meningitis in India showed that for CSF antigen or culture proven disease the annual incidence for children below 5 years is 7.1 per 100,000. But as one is dealing with infants below 1 year for vaccination, then the incidence is 32 per 100,0001. If we consider all cases of possible meningitis, the annual incidence for below 1 year is reported to be 357 per 100,0001. So, for a birth cohort of 25 million for India, the annual incidence for below 1 year population will be (32x250=8000) and that of possible meningitis (not proven by culture or antigen in C.S.F. 357x250=89250). Thus, the figures of culturally proven meningitis are 8000 cases annually and of possible meningitis 89250 cases. Same figures for Kerala would be 240 and 2670 respectively. The estimated mortality rate ranges not at 10% as given by J. Puliyel, but studies have shown it to be 20-25% and rate of severe neurological sequelae to be 30-40% as documented in NTAGI subcommittee recommendations2. This would mean, out of 8000 approximately 1600 to 2000 infants will die annually due to Hib meningitis and 2400 to 3200 infants will have neurological sequelae. If we take incidence of possible meningitis, we will have 17850 to 22312 deaths below 1 year. Figures for Kerala would be 48 to 60 and 534 to 669 deaths approximately for Hib meningitis and possible meningitis respectively. One knows that Haemophilus influenzae being a fastidious organism, culture may not always yield positive results. Hence, this statistics is meaningful. Haemophilus is reported to be a causative organism in many cases of bacterial meningitis and it is reported that 0.5 to 2.6% of all hospital admissions are attributable to bacterial meningitis3. Hib is also a leading cause of pneumonia in India accounting for 13-19% of pneumonia and lower lung disease4.
b) Now, let us analyse the situation in Kerala, India after pentavalent vaccine was introduced. The population of the State is 33300,000 and births are 566,100 approximately. The number of doses of pentavalent vaccine given in 2012 were 1500000 approximately and reported deaths following vaccination 9 (6 of 2012 & 3 of 2013). It is important to note that causality could not be established and deaths were probably not related to vaccine.
Considering the infant mortality in the State to be 13 per 1000, it would be expected that around 7359 infants would have died in 1 year. Out of these, 6 were temporarily associated with vaccine though not related to it. Comparing the two figures, even presuming that the deaths occurred due to vaccine which they are not, one realizes that the burden of Hib disease – meningitis and pneumonia is much more and safety of the vaccine is considerable. So, statistically, one is on sound footing and safety is established.
c) Coming to the question of NTAGI report of pentavalent vaccine being introduced only in two States in the country, it may be noted that the report states “As simultaneous nationwide rollout will be logistically challenging, Hib should be introduced in a phased manner beginning as soon as possible2. Thus, the policy of the Government of India in introducing the vaccine Statewise seems totally justified on logistic grounds.
d) Cost effectiveness of the vaccine has been worked out using a mathematical model by Gupta M et al, India and the sensitivity analysis showed that Hib vaccine introduction remained cost effective for India5.
We hope this clarifies the position of pentavalent vaccine use for the country.
Dr. M.A. Phadke
MD, DCH, FIAP, MRCP(UK), FRCP CH(UK), MNAMS
- Sr.Adv.NRHM, Maharashtra, UNICEF Consultant, Adj. Prof. MUHS, Independent Director, Serum Institute of India Ltd., Pune, Vi.Scientist, Haffkine Institute, Parel, Mumbai & Former Vice-Chancellor, Maharashtra University of Health Sciences, India.
Dr. Pramila Menon
- Associate Professor & Head, Dept. of Genetics, Immunology, Biochemistry & Nutrition, Pune Regional Centre, Maharashtra University of Health Sciences, Pune, India
1) Minz S, Balraj V, Lalitha M K, Murali N, Cherian T, Manoharan G, Kadivan S, Joseph A, Steinhoff M C. Incidence of Haemophilus influenzae Type b meningitis in India. Ind. J. Med. Res. 2008; 128(1): 57-64.
2) Kant Lalit. NTAGI Subcommittee Recommendations on Haemophilus influenzae Type b (Hib) Vaccine introduction in India. Indian Pediatric 2009; 46(17):945-952.
3) Kabra S K, Kumar P, Verma I C, Mukherjee D, Chowdhary B H, Sengupta S et al. Bacterial meningitis in India: an IJP survey, Indian J. Pediatr 1991; 58:505-518.
4) Patwari A K, Bisht S, Srinivasan A, Deb M, Chattopadhya D. Aetiology of pneumonia in hospitalized children. J Trop Pediatr 1996; 42: 15-20.
5) Gupta M, Priya S, Kumar R, Kaur M. Cost effectiveness of haemophilus influenzae Type b (Hib) Vaccine introduction in the universal immunization schedule in Haryana State, India. Health Policy Plan 2013; 28(1):51-61.
Competing interests: Authors have conducted various vaccine trials for over 2 decades,are on several vaccine boards as independent directors, members of ethics committees DSMB.
Prof. and researcher, Haffkine Institute Parel Mumbai
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