Message Shared by RI Director Raffy Garcia to the Phil Rotary Governors in light of the reported 3rd case of polio
Having just come from Evanston, where I was able to talk to members of the International PolioPlus Committee, including Chairman Mike McGovern, who are all very aware of the situation in the Philippines, allow me to respond to the many questions being raised by well meaning senior Rotarians about the polio situation in the Philippines.
With the confusion being caused by the recent outbreak of the circulating vaccine derived polio virus in the Philippines, many are questioning the benefits of using the Sabine Oral Polio Vaccine (OPV) and are asking why we are not using the Salk Injectable Polio Vaccine (IPV).
When we first started PolioPlus some 35 years ago, WHO wanted Rotary to use the IPV. The first problem was the cost which was between $25 and $50 compared to OPV which is about $0.25 per dose.
The next problem is the difficulty in administration. IPV needs to be injected, requiring trained health workers. OPV is administered by administering two drops per dose (up to 6 doses over time) allowing even untrained Rotarians to administer the drops.
The third problem is availability. The world supply of IPV is very low. With our DOH, it is almost zero.
Let us not forget that if Rotary had followed the biddings of the WHO, we would never have eradicated 99.99% of polio by this time using the OPV.
Let us now examine the Philippine situation with the circulating vaccine derived type 2 polio virus.
First of all, what is this circulating vaccine derived polio virus? The responses below are derived from published reports which anyone can confirm.
On very rare occasions, if a population is seriously under-immunized, there are enough susceptible children for the excreted vaccine-derived polioviruses to begin circulating in the community. If the vaccine-virus is able to circulate for a prolonged period of time uninterrupted, it can mutate and, over the course of 12-18 months, reacquire neurovirulence. These viruses are called circulating vaccine-derived polioviruses (cVDPV).
The lower the population immunity, the longer these viruses survive. The longer they survive, the more they replicate, change, and exchange genetic material with other enteroviruses as they spread through a community.
If a population is fully immunized against polio, it will be protected against the spread of both wild and vaccine strains of poliovirus.
Episodes of circulating vaccine-derived poliovirus are rare. Over the past ten years – a period during which more than 10 billion doses of oral polio vaccine were given worldwide – cVDPV outbreaks resulted in fewer than 800 cases cases (data updated weekly). In the same period, in the absence of vaccination with OPV, more than 6.5 million children would have been paralysed by wild poliovirus.
So, what is vaccine-derived polio?
Oral polio vaccine (OPV) contains an attenuated (weakened) vaccine-virus, activating an immune response in the body. When a child is immunized with OPV, the weakened vaccine-virus replicates in the intestine for a limited period, thereby developing immunity by building up antibodies.
During this time, the vaccine-virus is also excreted. In areas of inadequate sanitation, this excreted vaccine-virus can spread in the immediate community (and this can offer protection to other children through ‘passive’ immunization), before eventually dying out.
On rare occasions, if a population is seriously under-immunized, an excreted vaccine-virus can continue to circulate for an extended period of time. The longer it is allowed to survive, the more genetic changes it undergoes. In very rare instances, the vaccine-virus can genetically change into a form that can paralyse – this is what is known as a circulating vaccine-derived poliovirus (cVDPV).
It takes a long time for a cVDPV to occur. Generally, the strain will have been allowed to circulate in an un- or under-immunized population for a period of at least 12 months. Circulating VDPVs occur when routine or supplementary immunization activities (SIAs) are poorly conducted and a population is left susceptible to poliovirus, whether from vaccine-derived or wild poliovirus. Hence, the problem is not with the vaccine itself, but LOW VACCINATION COVERAGE. If a population is fully immunized, they will be protected against both vaccine-derived and wild polioviruses.
Since 2000, more than 10 billion doses of OPV have been administered to nearly 3 billion children worldwide. As a result, more than 13 million cases of polio have been prevented, and the disease has been reduced by more than 99%. During that time, although 24 cVDPV outbreaks have occurred in 21 countries (including the Philippines now), this resulted in fewer than 760 VDPV cases!!! Thank God for the OPV!
Until 2015, over 90% of cVDPV cases were due to the type 2 component in OPV. With the transmission of wild poliovirus type 2 already successfully interrupted since 1999, in April 2016 a switch was implemented from trivalent OPV to bivalent OPV in routine immunization programmes. The removal of the type 2 component of OPV is associated with significant public health benefits, including a reduction of the risk of cases of cVDPV2.
THE SMALL RISK OF CVDPVs PALES IN SIGNIFICANCE TO THE TREMENDOUS PUBLIC HEALTH BENEFITS ASSOCIATED WITH OPV.
Every year, hundreds of thousands of cases due to wild polio virus are prevented. Well over 10 million cases have been averted since large-scale administration of OPV began 20 years ago.
Circulating VDPVs in the past have been rapidly stopped with 2–3 rounds of high-quality immunization campaigns.
The solution is the same for all polio outbreaks: immunize every child several times with the oral vaccine to stop polio transmission, regardless of the origin of the virus.
So, what should Rotarians do under the present circumstances?
We should continue to support PolioPlus. We should insist on the full and complete immunization of all our children using the OPV available in the country.
Thanks to Rotary!
We will END POLIO FOREVER!!