With its last reported case of a wild polio infection dating back to January 2011, India completed the three-year mandatory period that a country needs to stay free of fresh infections in 2014, allowing it to be endorsed as a country which has eradicated the virus.
India will now introduce injectable polio vaccine (IPV) in its universal immunisation programme. This is a part of the World Health Organization’s polio endgame strategy. WHO has defined a staged approach which paves the way for polio eradication. Oral Polio Vaccine (OPV) cessation will eventually take place following a gradual decrease of OPV use, and once circulation of wild poliovirus has stopped fully. Currently, the introduction of one dose of IPV in routine immunisation is part of GPEI’s Endgame Strategic Plan for 2013-2018 and relates to the cessation of OPV2 vaccination through the switch from trivalent to bivalent OPV.
In light of this, we recently had the opportunity of discussing these developments with Dr Joël Calmet, who is the Senior Director of Communication, Medical and Scientific at the Global Communication Department at Sanofi Pasteur. He is in charge of communications with specific focus on polio eradication, and he shares his views with us on the status of polio eradication in the world. He has worked on polio in India since the early 1990s and was, for many years, responsible for Sanofi Pasteur’s cooperation with the WHO and with other polio eradication partners.
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Q: What is the current status of polio eradication?
A: When one sees the current figures, there is reason to be optimistic. We are ending the high season of transmission and there has been significant progress to date. Nigeria is no longer endemic, and this is great news for the entire African continent. There are no more sources of reintroduction of wild polio locally which is significant.
In Asia, only Pakistan and Afghanistan are endemic and there is significant progress in these two countries as well. We are hopeful that we will see the last case of wild polio in 2015.
Q: Why is India considered so important for the eradication of polio?
A: India has always been very much considered to be the heart of the battlefield for the eradication of polio. There are many reasons for this. India is the second most populated country in the world. All of the challenges in public health are crystallised in India, such as density of population and the discontinuity of the health systems. For polio and also for other infectious diseases, a big chunk of the disease burden was in India. Therefore, the country is very crucial for the successful eradication of polio globally.
Q: Why is the switch to IPV so important?
A: I think there are three reasons why this is important.
Firstly, the final step towards the victory over polio will be the removal of all OPV in the world. It will be important to be free, not only of the wild polio cases, but also of the very rare cases derived from the use of OPV. The final victory over polio will be made possible with this global switch to the IPV. As a matter of equity, I would not be happy if, after polio is eradicated globally, half of the world is protected by IPV and the other half is not.
The second reason is about improving the efficacy of the current routine immunisation schedule. After adding IPV to the OPV schedule, you are gaining efficacy, not only from the point of view of the protection of the individual, but also from stopping the possibility of transmission of the virus from an immunised individual.
The third reason is that introduction of IPV will allow us to remove wild polio virus type 2 from the traditional trivalent OPV. This virus is extinct in the wild so when it disappears from the vaccine, it will be gone permanently
Q: What should India do next? What is the new challenge for India?
A: The next step is to make the switch to IPV in a homogenous way all across India. This is why India is so important because you could be in a situation in the near future when you have to switch from the trivalent to the bivalent, where you create the exact condition for the resurgence of CVDPV (vaccine-transmitted polio) type 2. Implementing this switch effectively and appropriately is far more complicated in India than anywhere else in the world.
Q: Looking back, what has changed or should have changed over the years since the polio vaccine was introduced?
A: We are now in a strange situation where the vaccine is causing more cases than the native disease. This is not because there are so many vaccine-derived cases but because eradication has been such a success — cases have fallen so fast in wild polio. This has been the biggest change.
Q: India is quite proud of its achievement in polio. But do you think that it could have eradicated polio much sooner than it already has?
A: This is highly speculative. One of the challenges that we face is related to the properties of OPV itself. And not only on the safety but also the efficacy side. We have had incidences in the past in the past where children were contracting polio after 7 – 10 doses of monovalent OPV 1.This indicated that OPV had limitations, and we could, maybe, have hastened things back then by an earlier introduction of IPV. That could have been an option. However, when you are working on achieving global targets of eradication, you need consensus. If a consensus had not been obtained, the rest would all have been immaterial. India was an important part of the consensus
Q:We have seen so many plans to end polio. Why should this work when all others have failed so far?
A: The first reason is really the improvement in the efficacy of the current schedule. WHO has defined a staged approach in which OPV cessation will eventually take place following a gradual decrease of OPV use and once circulation of wild poliovirus has stopped fully.There is a significant improvement when you switch from trivalent OPV to bivalent OPV and add one dose of IPV to the current schedule.
Secondly, we have seen a lot of innovative strategies being adopted to strengthen mobilisation. If we take India as an example, the polio eradication campaigns included bivalent OPV. And, not only was the vaccine more efficacious, but innovative strategies were used to mobilise all the health and social workers together as a part of the campaign. Therefore, it is important to bring innovation to the table to succeed in mobilising the health care workers and community to ultimately achieve the goal of polio eradication.
Q: Are your sure that there will be enough of the new IPV vaccine for the huge number of babies born every year in India? This is a gigantic task really.
A: It is a gigantic task. India as we said is a challenge on its own. Sanofi Pasteur has been present in India from the early 80s and we did know that, at some point in time, we would have to face these challenges and prepared a lot to meet them head-on. Of course, we are not alone in this game. But our industrial plan includes India. So, yes: I am confident
Q: Are you confident that the demand will be met?
A: Yes, we are confident. The only real issue is to match the timelines, which are extremely challenging because we will have to succeed in the big bang, which takes place in two weeks in the world.
[The big bang is the transition from trivalent OPV, containing all three strains of the wild polio virus, to bivalent OPV, containing only the two strains which exist in the wild. This must be a very short and globally-coordinated period because, otherwise, children given trivalent OPV might excrete type 2 virus and infect other children who had not been immunised against type 2]
The pathway is quite narrow, and specifically when you deal with India, any move such as this is very demanding. IPV introduction in India is starting. Being optimistic, it will take some months to achieve the switch, but all the partners are very aware of the challenges they face and are working together to achieve a common goal.
Q: The effort to end polio is costing billions, with very few people at risk. Some would argue that it would be better for the world to spend the money elsewhere in public health, What are your thoughts on this?
A: When you look at the disease burden for India, it is a reasonable question. In my opinion, India has taken responsibility for polio eradication and this is extremely honourable on their part. In other countries, all the external partners are the dominant sources of supply and funding. The question about money being used better elsewhere – this money is only available for eradication so it is not money that would have been available for any other disease other than eradication of polio and therefore, it is not money wasted.
Regarding the Indian resources having been mobilised elsewhere – I think this is more of an Indian debate that I am not qualified to answer. There are pros and cons. It is true that there are many other diseases in India that could have benefitted from the resources allocated for polio. However, when you see the progress that has been made by India in terms of public health policy, mobilisation and implementation, there have been a lot of lessons learnt in the process of polio eradication . But I will refrain from making any judgments as I am not an Indian citizen.
Overall, is it worth spending resources to eradicate polio? Of course. It looks very expensive per case averted today because there are so few cases. A GPEI study says that, if eradication falters, there could be more than 200,000 cases a year across the globe by 2025. Then the cost of immunisation per case averted would look very low. Is that what we want? Of course not.
A US study a few years ago estimated that the American economy has benefitted by billions of dollars a year from eradicating polio. Other work suggests this will be true on a global scale. The costs are small compared to the benefits.
Q: As India prepares to launch IPV this month. What do you think is its most critical and pressing challenge ahead?
A: The big challenge is to be absolutely sure that no remaining trivalent OPV will be used after the big bang. Knowing that India has used a huge quantity of this product and now, will have to stop completely within two weeks, is an immense challenge. Until now, the entire Indian health system has been encouraged to use trivalent OPV. Now, within two weeks, they will have to change the consumption and communication around trivalent OPV and this is a mammoth task.