Neisseria meningitidis causes invasive diseases like meningococcemia and meningitis with a case fatality rate of 10-15% and a disability rate of 11-19% among survivors [1]. Although the bacterium largely continue to be sensitive to antibiotics but rapid course of illness and emerging antibiotic resistance warrants that the disease be prevented as far as possible [2,3]. Currently, several vaccines against meningococcus are available, but one has to choose wisely to ensure maximum efficacy. At least five serotypes (A, B, C, Y and W135) have been associated with invasive meningococcal disease (IMD) worldwide. Polysaccharide vaccine (against 2 or 4 serotypes) have been available for quite some time but have the inherent disadvantage of lacking T cell response, resulting in their lack of utility in children below 2 years of age, and also failing to confer immunological memory [1]. Attempts to conjugate the polysaccharide antigen with protein have resulted in successful development of conjugated monovalent or quadrivalent vaccines against different serotypes of meningococci. Quadrivalent vaccine with polysaccharides of serogroup A, C, Y and W 135 conjugated to Diphtheria toxoid has been in use for adolescents (11-14 years) in USA since 2005 [4]. Although having 80-90% protective efficacy in first year after vaccination, the same has been found to decline to 60-65% in the fifth year, warranting a recent recommendation of a booster dose at 16-18 years of age [5].

Yadav, et al. [6]. – in a study reported in this issue of Indian Pediatrics – have shown 90-100% sero-efficacy of this quadrivalent vaccine in Indian children, adolescents and adults. The authors have chosen to estimate antibodies in rabbit serum where the protective levels are highly unpredictable and hard to define. Generally, bactericidal titers of 1:4 in human serum are considered protective against IMD [7]. Titers as high as 1:128 in rabbit serum are needed to assure that a titer of 1:4 are present, if measured with human serum [8]. Despite this shortcoming, the results of this bridging study are adequately reassuring regarding efficacy and safety of this vaccine in the Indian context.

However, before considering the introduction of this vaccine in the National program or even in the list of ‘optional vaccines’ of schedule recommended by Indian Academy of Pediatrics, the potential utility of this vaccine in our country needs to be examined. Epidemiology of meningococcal disease in India appears to be distinctly different from that in USA. While in USA, the disease mostly occurs in a sporadic manner with serotypes B, C and Y accounting for about 30% cases each, occasional small outbreaks among college students are usually due to serotype B [4]. In contrast, all the epidemics in India since 1930 have been due to serotype A [2]. Occasional cases of meningitis due to serogroup B are reported but to the best of our knowledge, cases of IMD due to serotype C, Y or W 135 have not been reported from our country [9]. Thus, we have predominantly serotype A IMD in our country, a situation not very different from other Asian countries and Sub-Saharan belt in Africa [1,10].

Different countries in the world have used different monovalent or polyvalent polysaccharide conjugated vaccines depending on their disease epidemiology. While USA is using the quadrivalent vaccine, a serogroup B polysaccharide conjugated vaccine has recently been recommended for routine use in UK for infants, and is being considered for interrupting the ongoing epidemic in Princeton University in USA [11]. A serogroup C monovalent vaccine has been used successfully in several countries of the world like Spain, Italy, Greece, France, Canada, Australia, Brazil and Argentina [12]. It would seem logical that with known preponderance of serogroup A IMD in our country, a monovalent conjugate vaccine targeted against serogroup A meningococcus will be more useful and cost effective in our country. A novel meningococcal serogroup A conjugated vaccine (PsA-TT, MenAfrVac) – introduced in Burkina Faso [13], Mali and Niger in 2010 – resulted in 71% (hazard ratio 0.29, 95% CI 0.28,030; P<0.0001) decline in risk of meningitis and a 64% decline in risk of fatal meningitis. No case of serogroup A IMD occurred in vaccinated individuals and no serotype replacement was seen. The incidence of laboratory confirmed serogroup A meningococcal meningitis dropped to 0.1 per 100,000 representing a 98.6% reduction [13].

Funding: None; Competing interest: None stated.

 1. Granoff DM, Harrison LH, Borrow R. Meningococcal vaccine. In: Plotkin SA, Orenstein WA, Offit PA, editors. Vaccines. 5th ed. Philadelphia:Saunders; 2008. p.399-434.

2. Manchanda V, Gupta S, Bhalla P. Meningococcal disease: history, epidemiology, pathogenesis, clinical manifesta-tions, diagnosis, antimicrobial susceptibility and preven-tion. Indian J Med Microbiol. 2006;24:7-19.

3. Dass H, Deka NM, Khyriem AB, Lyngdoh WV, Barman H, Duwarah SG, et al. Invasive meningococcal infections: An analysis of 110 cases from a tertiary care centre in North East India. Indian J Pediatr. 2013;80:359-64.

4. Pickering LK, Baker CJ, Long SS, McMillanassociate JA, editors. Red Book: 2006 Report of Committee on Infectious Diseases. 27th ed. Illinois: American Academy of Pediatrics; 2006.

5. Centres for Disease Control and Prevention. Meningococcal Vaccination: Who Needs to be Vaccinated? Available from: http://www.cdc.gov/vaccines/vpd-vac/mening/who-vaccinate.htm. Accessed May 19, 2014.

6. Yadav S, Manglani MV, Narayan DHA, Sharma S, Ravish HS, Arora R, et al. Safety and immunogenicity of a quadrivalent meningococcal conjugate vaccine (MenACYW-DT): A multicenter, open-label, non-randomized, phase III clinical trial. Indian Pediatr. 2014;51:451-6.

7. Goldschneider I, Gotscchilch EC, Artensein MS. Human Immunity to meningococcus: The role of humoral antibodies. J Exp Med. 1969;129:1307-26.

8. Santos GF, Deck RR, Donnelly J, Blackwelder W, Granoff DM. Importance of complement source in measuring meningococcal bactericidal titers. Clin Diag Lab Immunol.2001;8:616-23.

9. Aggarwal M, Manchanda V, Talukdar B. Meningitis due to Neisseria meningitides serogroup B in India. Indian Pediatr. 2013;50:601-3.

10. Halperin SA, Bettinger JA, Greenwood B, Harrison LH, Jelfs J, Ladhani SN, et al. The changing and dynamic epidemiology of meningococcal disease. Vaccine. 2012;30(Suppl.2):B26-36.

11. JCVI Interim Position Statement on Use of Bexsero® Meningococcal B Vaccine in the UK. Available from: https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/224896/JCVI_interim_statement_on _meningococcal_B_vaccination_for_web.pdf . Accessed May 19, 2014.

12. Pizza M, Tora LD, Wassil J. Advances in meningococcal vaccines. Clin Pract. 2012;9:101-17.