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Polio Free


Polio Vaccines



There are two types of vaccines against polio—oral polio vaccine (OPV) and inactivated polio vaccine (IPV) delivered via injection.

OPV contains an attenuated (weakened) virus that can mutate into vaccine-derived poliovirus (VDVP) that can circulate and cause polio infections in a community.

VDPVs will continue unless global community makes the transition to IPV after wild poliovirus is eradicated.

OPV can also result in vaccine-associated paralytic polio (VAPP), although this is rare, occurring once for every 2.7 million first doses of the vaccine.

Most wealthy countries use IPV, but because the current price (>$3/dose) is out of reach for low- and middle-income countries, they rely on OPV ($.13 -.17/dose).

To complete eradication and to ensure protection post-eradication, new tools are needed:

Lower cost OPV for maintaining population immunity, for stamping out pockets of endemic wild poliovirus transmission, and for controlling outbreaks.

Much more affordable IPV to contain and end VDPVs and sustain population immunity post eradication.

Affordable IPV-containing pediatric combination vaccines for future birth cohorts in low-income countries.





Articles:
Immunogenicity of supplemental doses of poliovirus vaccine for children aged 6—9 months in Moradabad, India: a community-based, randomised controlled trial
The Lancet Infectious Diseases, Volume 12, Issue 2, Pages 128 - 135, February 2012
doi:10.1016/S1473-3099(11)70190-6 - Published Online: 08 November 2011

Currently there are two polio vaccines that are in use throughout the world to fight against polio. Jonas Salk, the man who invented the first, started his work on a vaccine in 1955. The vaccine worked in two steps: first a dose of killed polio virus is injected, and then an oral polio vaccine must be taken which contains a live but much weakened form of the virus. This vaccine was first tested in 1957 on humans, and was later liscensed in 1962.

Then came along another vaccine that was developed by Sabin. This live-virus vaccine quickly became to more popular route of the two for 4 main reasons:

1. Due to it's live state it has the ability to spread and to infect other individuals who have not been vaccinated. This sounds bad, but in the spread, it allows the remote body to build up some immunity to the virus.

2. Due to the fact that the oral vaccine performs its magic in the gut, it works on immunity there in the central system which in turn reduces the spread of the virus on the outside. If the polio vaccine is injected directly into the bloodstream it will immunize the inividual, however it does not not reduce his or her ability to spread the virus.

3. Everything is a matter of money these days, especially when it comes to healthcare. Sabin's "live" vaccine was cheaper than Salk's "dead" vaccine.

4. The last reason for the increased popularity of Sabin's vaccine is that the oral vaccine is a lot easier to widely administer to the general population than the injected vaccine. This means that patients are more likely to complete the series of vaccinations that are required to attain full immunity.

Sabin's vaccine is the standard treatment for polio to date. The dead virus was able to bring Polio to terms, however it was the live-virus vaccine that was able to completely eliminate the wild spread of the polio virus in the United States.


Polio Free



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