Influenza vaccination is aimed at reducing influenza-related morbidity
and mortality, especially in vulnerable groups. Indian Academy of
Pediatrics, Advisory Committee on Vaccines and Immunization Practices
(ACVIP) recommends inactivated influenza vaccine (IIV) or live
attenuated influenza vaccine (LAIV) for certain high-risk children [1].
It recommends the best time to vaccinate is as soon as the new vaccine
is released and available in the market just before the onset of rainy
season.
Preventing influenza disease is challenging, as
influenza virus is characterized by frequent mutations due to antigenic
drifts and antigenic shifts. To ensure optimal vaccine efficacy against
prevailing strains, the antigenic composition of the vaccine is revised
twice annually in both the northern hemisphere (NH) and southern
hemisphere (SH), and adjusted to the antigenic characteristics of the
circulating viruses obtained within the WHO Global Influenza
Surveillance and Response System (GISRS). This allows the vaccine
manufacturers 4-6 months to manufacture the vaccine for the specific
hemisphere [2].
As per WHO, India is categorized in SH tropical Asia
vaccination zone. The vaccine strains may be similar for both hemisphere
formulations or different depending on the circulating strains. If the
composition of both the hemisphere formulations is same, as happened in
2017, one can use any of the latest available vaccine from either
hemisphere. In India, both NH and SH influenza vaccines are available.
For this season, WHO has recommend influenza vaccine
with different strains for the NH and SH. At present, influenza vaccine
meant for those living in northern hemisphere, is available and being
used in India. WHO recommendations on vaccine formulation for India
strongly favor the Southern hemisphere vaccine rather than the one for
Northern hemisphere. Not many pediatricians are aware of these facts and
continue to prescribe the available vaccine without going through the
details. Prescribing the currently available NH vaccine in India is not
scientifically correct and will not serve the purpose of vaccination.
There is a need to educate not only the parents but also the
pediatricians about using the appropriate influenza vaccine, and
prescribe it after verifying the scientific facts rather than use
whatever is available.
References
1. Indian Academy of Pediatrics, Advisory Committee
on Vaccines and Immunization Practices (ACVIP), Vashishtha VM, Kalra A,
Bose A, Choudhury P, Yewale VN, Bansal CP, Gupta SG. Indian Academy of
Pediatrics (IAP) Recommended Immunization Schedule for Children Aged 0
through 18 years – India, 2013 and Updates on Immunization. Indian
Pediatr. 2013;50:1095-108.
2. WHO Recommendations on the Composition of Influenza Virus
Vaccines. Available from:
http://www.who.int/influenza/vaccines/virus/recommendations/en/.
Accessed September 15, 2018.