UPDATE ON POLIO INFECTION AND VACCINATION
1. Polio virus
infection was a common cause of paralysis of legs and arms in many people
across the world (including India) until the last decade.
2. As of January
2016, polio has been eliminated from all countries of the world except Pakistan
and Afghanistan. The last case of Polio in India was seen in 2011.
3. There are 3
types of polioviruses called as types 1, 2 and 3. No polio infection has
occurred due to type 2 poliovirus since 1999. The last case of Type3
virus-related polio was seen in 2012. So, at present, all polio infections are
caused by type 1 poliovirus.
4. So, now, there
is no need to use vaccine against all three types of viruses. The current oral
polio vaccine (bivalent oral polio vaccine) gives protection against types 1
and 3 poliovirus types, and that is sufficient.
5. It is important
to avoid using the older trivalent polio vaccine (which gave immunity against
all three polio virus types), as older vaccine was responsible for rare
complications called as vaccine associated paralytic polio (VAPP). In India,
trivalent polio vaccine will be removed from April 2016, and only bivalent OPV
would be available.
6. There are two
types of polio vaccines- inactivated polio vaccine (IPV) and oral polio vaccine
(OPV). As the name suggests, in IPV, the virus is in inactive state, and there
is no risk of VAPP with this. So, in countries with no polio infection, it is
better to use IPV. However, IPV does not prevent outbreaks of polio. So, in
countries where polio infection is still present or there is a risk of
epidemic, OPV is preferred.
7. In India, OPV
is the vaccine of choice, given at birth, 6 weeks, 10 weeks and 14 weeks of age
to children. IPV is optional and can be taken at 14 weeks of age along with
third dose of DPT and OPV.
8. World Health Organization (WHO) has planned comprehensive strategies aiming eradication of polio to make the world free of polio by 2018. When this happens, polio would become the second infection to be eradicated (after small pox). The last case of small pox occurred in 1975 in Bangladesh.
8. World Health Organization (WHO) has planned comprehensive strategies aiming eradication of polio to make the world free of polio by 2018. When this happens, polio would become the second infection to be eradicated (after small pox). The last case of small pox occurred in 1975 in Bangladesh.
