One reason parents often avoid the polio vaccine is the fear that their child may actually contract the disease from the vaccine. Once upon a time, I was told that this live vaccine could actually be contracted through changing diapers. Like much information about vaccines that is shared, sometimes it is hard to separate fact from fiction.
In the US, the live polio vaccine has not been used for a dozen years.
The Centers for Disease Control (CDC) reports:
There are two types of vaccine that protect against polio: inactivated polio vaccine (IPV) and oral polio vaccine (OPV). IPV, used in the United States since 2000, is given as an injection in the leg or arm, depending on patient’s age. Polio vaccine may be given at the same time as other vaccines. Most people should get polio vaccine when they are children. Children get 4 doses of IPV, at these ages: 2 months, 4 months, 6-18 months, and booster dose at 4-6 years. OPV has not been used in the United States since 2000 but is still used in many parts of the world.
India is one of those countries that still uses the OPV.
India has worked hard to eradicate polio through vaccinations, and the country earned polio-free status recently, that is free of polio not caused by the very vaccines meant to eradicate it.
Yesterday, the Times of India reports:
India has reported its first case of vaccine derived polio virus (VDPV) infection of 2012. A five-month-old child from the Murshidabad district of West Bengal has got infected with the virus after taking the oral polio vaccine…
Oral polio vaccines (OPV) contain a weakened version of poliovirus, activating an immune response in the body. A vaccinated person transmits the weakened virus to others, who also develop antibodies to polio, ultimately stopping transmission of poliovirus in a community. According to experts, in very rare instances, the virus in the vaccine can mutate into a form that can paralyze — this is what is known as a VDPV.
As a result, India may stop using this particular polio vaccine. Today, the Times of India explained this game change:
The India Expert Advisory Group (IEAG) on polio has recommended that the nation should stop the use of trivalent oral polio vaccine(TOPV), and only rely on the oral bivalent variant.
Experts say chances of vaccine derived polio virus infection (VDPV) are higher with the use of TOPV (that targets all three strains of polio virus – P1, P2 and P3) against the bivalent vaccine (that targets only P1 and P3)…
“The plan to shelve the TOPV is part of our end-game strategy. India recently was taken off the list of polio endemic countries by the WHO. The recommendation to shelve TOPV is in order to ensure that we don’t even report a single VDPV case. The chances of VDPV infections are higher with the use of TOPV,” said a health ministry official.
Also, the vaccine targets the P2 strain of polio that was eradicated from India in 1999.
Clearly, this vaccine has prevented paralysis and death, which the CDC states only occurs in “fewer than 1% of polio cases”. Interestingly, “95% of persons infected with polio will have no symptoms.”
India has not reported a “wild” case of polio since January 13, 2011. Such eradication is called “one of the greatest achievements in public health in the 21st century”.
What concerns me about cases such as this and vaccinations overall in less-privileged countries is why are they still administering shots no longer considered safe in the US?
I assume it boils down to money. Just as thimerosal (mercury) preserved vaccines are still administered in third world countries funded by US billionaires but are no longer considered safe in the US, live polio oral vaccines are still prevalent around the globe. If it isn’t safe for our kids, why is it safe in the third world?
amateur fact geek says
You asked: “What concerns me about cases such as this and vaccinations overall in less-privileged countries is why are they still administering shots no longer considered safe in the US?”
Your assumption that it is because of money is wrong. The U.S. and other well-off countries used the oral polio vaccine until long after those countries had interrupted wild polio virus transmission. The U.S. used the oral polio vaccine from the early 1960s until it was completely phased out in the year 2000 — 21 YEARS after interrupting the spread of indigenous wild-type polio viruses in the U.S. in 1979. (see http://www.ncbi.nlm.nih.gov/pubmed/22298920 ).
The South American countries have also interrupted the spread of indigenous wild polio — but for both financial and practical reasons continue to use OPV, and plan to do so until polio is eradicated globally. The U.S. and other well-off countries using only the “killed vaccine” are lucky that they can both afford to use the more-expensive vaccine, and also manage the vastly more difficult task of using it (rather than OPV) to vaccinate virtually all their children. We all hope the entire world will someday need neither the OPV NOR the IPV to prevent the risk and reality of polio.
Jennifer Lance says
This statement also applied to the mercury vaccines that were shipped off to Africa and other places after being phased out by the US.
The issue of using OPV (oral vaccine) as opposed to IPV (injectible vaccine) is basically one of logistics. One thing that westerners have to keep in mind is that many places india do not really have a health delivery system of any kind. During polio drives India is currently immunizing 170 million children. Besides the fact that it costs 20 times more, the bigger problem is that using injections is far more time consuming, and requires training. There is likely also to be far more resistance from people. Almost surely we cannot achieve the coverage level anywhere near what is achieved with OPV.
The ethical issues involved here are tricky. Do you use a vaccine which may cause a few vaccine derived cases, but provides a pathway to eradication? Or do you use a vaccine that is more effective / safe for an individual, but with a much reduced chance of covering everyone, and which therefore may never lead to eradication?