ADDENDUM ON CIRCULATING VACCINE-DERIVED POLIOVIRUS (cVDPV2) 

The polio case numbers used by Rotary, refer exclusively to cases of polio caused by wild poliovirus in Pakistan and Afghanistan, unless otherwise specified. For example, when we say that there were 174 cases of polio in Pakistan and Afghanistan in 2019, this means “174 cases of polio caused by the wild poliovirus.”

FREQUENTLY ASKED QUESTIONS: VACCINE-DERIVED POLIO

How do VDPVs circulate? 

· Circulating VDPVs occur when polio immunization activities are poorly conducted, or children are inaccessible and not enough children are reached with vaccine to ensure full immunity. As a result, a population is left under-immunized. 

· cVDPVs can occur if the weakened strain of the virus originally contained in OPV is allowed to circulate among an under-immunized population for a long time, allowing the virus to regain strength and genetically revert into a form that can cause paralysis. 

· If a population is fully immunized, they will be protected against both vaccine-derived and wild polioviruses. 

Why were there so many cVDPV outbreaks last year? 

· The current outbreaks are driven by several factors, including insufficient routine immunization coverage, mobile populations, and low-quality immunization campaigns. 

· However, it is important to remember that cVDPVs are still extremely rare. More than 20 billion doses of OPV have been given to more than one billion children worldwide in the last decade, averting 650,000 annual cases of paralysis and some 30,000 childhood deaths during that period. 

Is the oral polio vaccine safe? 

· OPV is a safe and effective vaccine that is responsible for eliminating over 99% of polio cases worldwide and eradicating wild polioviruses type 2 and type 3. 

· We would not be where we are now without OPV. 

Why does the GPEI continue to use OPV when it causes polio and IPV does not? 

· Unlike IPV, OPV has a unique ability to stop person-to-person spread of poliovirus, so it is vital to achieving eradication. Additionally, it is easy to administer and can be distributed quickly on a large scale by health workers and volunteers. 

o IPV also plays an important role in protecting children from polio. Both IPV and OPV will play a role in the global eradication of polio. 

· cVDPVs can occur if the weakened strain of the virus originally contained in OPV is allowed to circulate among an under-immunized population for a long time, allowing the virus to regain strength and genetically revert into a form that can cause paralysis. Therefore, the key risk factor is low population immunity. 

o If a population is fully immunized, they will be protected against both vaccine-derived and wild polioviruses. 

What is Rotary and the GPEI doing to address outbreaks? 

· To address the current cVDPV2 situation, the GPEI is developing a new response strategy and evaluating new measures to more effectively address outbreaks. 

· A new vaccine is being developed – novel oral polio vaccine 2 (nOPV2) – which would have a substantially lower risk of seeding new outbreaks of cVDPVs. 

· The new vaccine is currently in phase II clinical trials, and as long as further trials continue to yield positive results, nOPV could be used as early as mid-2020. 

I learned of a polio outbreak in [COUNTRY]. Does it mean that [COUNTRY] is polio-endemic again? 

· A number of countries in Africa, Asia, and the Middle East are reporting outbreaks of vaccine-derived polio, which can occur in areas with under-immunized populations. 

· cVDPVs are not related to, nor indicative of, a re-emergence of wild poliovirus. 

How can you plan to declare the African region polio-free when cVDPV outbreaks are ongoing and increasing in number across the region? 

· When the ARCC officially finds Nigeria – the last polio-endemic country in Africa – wild poliovirus-free, it will be a critical step in the global eradication fight. 

· The ARCC mandate is looking at the wild poliovirus. There will be a separate process for the validation of the absence of cVDPVs 

· While Africa’s victory over wild polio is unprecedented, the work of protecting children across the region from all forms of polio must continue. The ongoing cVDPV outbreaks highlight the urgent need to continue that work. 

Could cVDPV outbreaks in Africa fuel fears of vaccine safety? 

· The GPEI and its partners work to build trust in vaccination and ensure all questions about vaccines are answered with the best available evidence. 

· To help facilitate this, the GPEI is continuing to implement extensive social mobilization and engagement strategies that underscore the safety and benefits of OPV. 

o cVDPV outbreaks are not a result of vaccine failure, but rather of inadequate vaccination coverage. If a population is sufficiently well-immunized, they will be protected from all forms of poliovirus, be it wild or vaccine-derived. 

· OPV remains our best tool for achieving eradication of the wild poliovirus. It is a safe and effective vaccine responsible for eliminating over 99% of polio cases worldwide over the past 30 years.