Module 1 Introduction to the polio endgame rationale and IPV vaccine Training for Inactivated Poliovirus Vaccine (IPV) introduction Module 1 Introduction to the polio endgame rationale and IPV vaccine

Learning objectives At the end of the module, the participant will be able to: Understand poliovirus transmission, poliomyelitis disease and global progress toward polio eradication Recognize the vaccines available against polio and the risks and benefits of each Describe the rationale for introducing IPV into the routine immunization schedule Duration 20 minutes

Key issues 1 2 3 4 5 What is polio disease? How is polio spread? What types of viruses exist and what vaccines do we have against them? 3 What is the status of polio eradication globally? 4 To the facilitator: Explain to the participants the key issues raised in this module. In this module you will learn more about polio disease and vaccine. We will provide you with answers to the following questions: What is polio disease? How is polio spread? What viruses exist and what vaccines do we have against them? What is the status of polio eradication globally? Why do we need IPV? Why do we need IPV? 5

What is polio disease? Polio (also called Poliomyelitis) is a highly infectious disease caused by a virus The virus invades the nervous system and can cause permanent paralysis Polio is spread through person-to-person contact and can spread rapidly through a community Most infected people (90%) have no symptoms or very mild symptoms However, one in 200 infections leads to permanent paralysis (can’t move parts of the body) and even death To the facilitator: Explain to the participants what polio disease is. Polio is a crippling and potentially fatal infectious disease caused by an acute viral infection. There is no cure, but there are safe and effective vaccines. The strategy to eradicate polio is therefore based on preventing infection by immunizing every child until poliovirus transmission stops and the world is polio-free. It invades the nervous system and can cause permanent paralysis in a matter of hours. Polio is spread through person-to-person contact and can spread rapidly through a community. Most infected people (90%) have no symptoms or very mild symptoms. One in 200 infections leads to permanent paralysis (can’t move parts of the body) and even death. www.immune.org.nz

How does poliovirus spread? Poliovirus infection is highly contagious Poliovirus is spread mostly by the fecal-oral route Primary mode of transmission – passage of the virus in stool to the mouth of another child Can also be spread through saliva or droplets from a sneeze or cough To the facilitator: Explain to the participants how polio is spread. Polio is spread through person-to-person contact typically through fecal-oral route but can also spread through droplets from saliva, sneeze or a cough. When a child is infected with wild poliovirus, the virus enters the body through the mouth and multiplies in the nasopharynx and intestine. It is then shed into the environment through oropharyngeal secretions for about a week and through faeces for 3 to 6 weeks. Poliovirus is highly infectious and nearly all susceptible household contacts of infected persons can acquire infection. Poor sanitation and water quality are risk factors to the disease transmission Transmission is especially high in situations of crowding and poor hygiene and sanitation. Child excretes virus in stool Virus transferred to objects from hands Virus transferred to another child’s hands Virus transferred ingested Next cycle of infection

How many polio cases are there? 1988 350,000 cases 125 endemic countries World Health Assembly resolved to eradicate polio 2013 416 cases reported (as of 14 May 2014) 3 endemic countries 7 countries with re-established transmission To the facilitator: Describe to the progress of polio from 1988 to 2013 and the remaining challenges. The eradication of polio is a top global health priority. Since the World Health Assembly (WHA) announced a goal to eradicate polio in 1988, thereby creating the Global Polio Eradication Initiative (GPEI), the number of polio cases has drastically declined from ~350,000 cases per year in 1988 to only 416 cases in 2013 (as of 20 Nov 2013) Two important aspects of the current global situation of polio warrant ongoing use of OPV until polio transmission is interrupted. First, WPV is still endemic in three countries (Pakistan, Afghanistan, and Nigeria) that continue to be reservoirs for re-infecting other countries worldwide Second, in 2013 and 2014, polio cases were also detected in seven additional countries (Somalia, Kenya, Ethiopia, Cameroon, Syria, Iraq, and Equatorial Guinea) that were previously polio free. Until polio transmission is interrupted in all of these high transmission settings, OPV will be a critical component of the Eradication Plan. 6

Types of polioviruses Wild poliovirus (WPV) – 3 serotypes Type 1 – 416 cases in 2013 (this is the only type of WPV in circulation today) Type 2 – eliminated in 1999 Type 3 – last case reported in 2012 (more time is needed to certify eradication) To the facilitator: Explain to the participants the types of polioviruses Polioviruses can be wild or vaccine-related. Wild polioviruses (WPVs) are those that circulate naturally and are classified into three distinct serotypes (type 1, type 2, and type 3). Since November 2012, all cases of polio related to wild virus have been Type 1. There has been no natural circulation of Type 2 WPV since 1999 when the last case was last detected in Aligarh, India. Type 3 WPV was last detected in November 2012, although absence of virus detection for one year is not sufficient for certifying eradication.

Types of Oral Polio Vaccines Trivalent OPV (tOPV): types 1, 2 and 3 most commonly used OPV in routine immunization globally Bivalent OPV (bOPV): types 1 and 3 commonly used in supplementary immunization activities (SIAs) Monovalent OPV (mOPV): type 1, 2 or 3 primarily used for SIAs in areas where only type 1 or type 3 is circulating OPV is still the primary vaccine for eradication

Paralysis associated with OPV OPV offers effective protection against polio, but… In very rare cases it can lead to paralysis Vaccine Associated Paralytic Polio (VAPP) Vaccine virus spontaneously changes and becomes capable of causing disease to the nervous system 1 case per 2.4 million vaccine doses administered 250-500 cases/year 40% of VAPP are from type 2 OPV Circulating Vaccine Derived Poliovirus (cVDPV) Rare outbreaks caused by person-to-person spread of vaccine strain, which mutates/changes to a highly transmissible form capable of causing disease to the nervous system, in areas/countries with low immunity against polio 97% of cVDPVs are from type 2 OPV Low coverage is one of the main factors for the occurrence of cVDPVs To the facilitator: Explain to the participants about the risks of OPV Although OPV offers effective protection against polio, it is a live attenuated vaccine and in very rare cases can lead to paralysis. There are two ways this can occur: 1) Vaccine Associated Paralytic Poliomyelitis (VAPP): refers to spontaneous reversion to neurovirulence of one of the attenuated Sabin viruses in OPV. For every 2.4 million doses of OPV administered, one vaccine recipient or a close contact is paralyzed. There are an estimated 250 – 500 VAPP cases globally per year. Of these, about 40% are caused by tOPV’s type 2 component. 2) Circulating Vaccine Derived Poliovirus (cVDPV) outbreaks: these rare outbreaks occur when a OPV strain is passed from person-to-person, mutating back to a neurovirulent and highly transmissible form. Almost all cVDPV outbreaks (97%) in recent years have been caused by a type 2 OPV-derived virus. Circulating VDPVs are widely transmitted in a community and are not likely to be related to contact with a recent vaccine recipient in contrast to VAPP which occurs in OPV recipients or their close contacts. Low coverage is considered as one of the main factors for the occurrence of cVDPVs. Other very rare forms include VDPVs in persons with a primary immunodeficiency syndrome (iVDPVs) and ambiguous VDPVs where the virus is genetically different than the Sabin strains implying prolonged circulation allowing those mutations to occur but is not known to be associated with an outbreak or immunodeficiency.

WPV and vaccine-related polio cases 2009-2014* Through the use of OPV, polio cases related to the wild poliovirus have decreased. Today the number of polio cases due to OPV is greater than those related to the wild virus. To the facilitator: WPV and vaccine-related polio cases 2009-2014 Although OPV is the appropriate vaccine until polio transmission is interrupted, with ongoing use of OPV and control of polio disease related to wild virus globally, the estimated number of polio cases related to OPV has exceeded those related to wild virus. Low coverage is considered as one of the main factors for the occurrence of cVDPVs. This graph shows reported paralytic cases of wild polio virus and estimated cases of paralysis associated with OPV (VAPP and cVDPV) assuming ongoing use of OPV. Blue bars depict WPV cases reported to GPEI as of 21 May 2014. Red line depicts cases of VAPP and cVDPVs estimated to occur based on midpoint of estimated cases of VAPP globally (250 to 500) and the average number of cVDPVs reported annually during 2008-2013. Post-interruption of WPV transmission * as of 21 May 2014

Polio eradication plan In May 2012 the World Health Assembly of WHO declared poliovirus eradication to be a global public health emergency Under this plan to achieve a polio-free world, they recommend that the use of OPV must eventually be stopped worldwide Type 2 OPV has the two risks: VAPP and cVDPV – and is no longer needed for eradication – hence the type 2 containing OPV will be eventually withdrawn from use OPV will be withdrawn in 2 phases beginning with type 2 OPV To the facilitator: Explain to the participants the Polio eradication Because of this very low but real risk of polio associated with OPV, if the world is to remain free of polioviruses following eradication, then use of OPV ultimately will need to be stopped. To curtail the risk of polio associated with OPV (cVDPV and VAPP), the Endgame calls for a withdrawal of vaccine in two phases: Phase 1: removal of type 2 component of OPV, through a global switch from tOPV to bOPV Phase 2: withdrawal of bOPV after the certification of eradication of wild polioviruses The phased withdrawal of OPV related to the epidemiology of WPV and vaccine-related cases of polio occurring globally in the past decade.

Polio eradication plan (continued) WHO’s Strategic Advisory Group of Experts (SAGE) recommends that all countries introduce at least one dose of IPV into their routine immunization schedule by the end of 2015, before type 2 OPV is withdrawn Rationale for this includes: To reduce risks of an outbreak after type 2 OPV vaccine withdrawal To help stop outbreaks quickly if type 2 virus is reintroduced To boost immunity against polio types 1 & 3 to protect populations and hasten eradication SAGE has recommended a global, coordinated withdrawal of the type 2 component of tOPV from immunization programmes by April 2016. For countries which use only trivalent OPV in their routine infant immunization programmes, this will require switching from trivalent OPV to bivalent OPV (containing only types 1 and 3) for that purpose. Prior to the tOPV-bOPV switch, SAGE recommends that all countries introduce at least one dose of IPV into their infant immunization schedules:

Comparison of OPV and IPV? Oral polio vaccine (OPV) Inactivated polio vaccine (IPV) Live, attenuated (weakened) virus Administered by drops Highly successful in reducing transmission in developing countries as part of eradication strategy Inexpensive Easy to administer Provides mucosal/gut immunity Protects close contacts who are unvaccinated Killed virus Administered by injection Highly effective Used commonly in developed countries More expensive than OPV Requires trained health workers Provides immunity through blood Carries no risk of VAPP or VDPV Both vaccines are needed to fully eradicate polio! To the facilitator Explain to the participants that there is are 2 vaccines against polio. The development of effective vaccines to prevent paralytic polio was one of the major medical breakthroughs of the 20th century. In general, there are 2 different vaccines to stop polio. Oral Polio Vaccine (OPV) is a Live weakened virus Inactivated Polio Vaccine (IPV) is a Killed virus administered by injection Both forms are needed today to stop the interruption of polio transmission. Once we stop polio, we will only need IPV. IPV is an inactivated vaccine and not a “live” attenuated vaccine. Therefore it carries no risk of vaccine-associated polio paralysis (VAPP) or cVDPV. Unlike OPV, immune response for IPV does not vary substantially between industrialized and tropical developing country settings.

Why IPV? IPV does not cause any paralysis and is a very safe vaccine IPV introduction sets the stage for ending OPV use entirely after WPV eradication has been achieved When use of OPV is eventually stopped, IPV will continue to provide full protection Introducing IPV to our community also helps us remind caretakers about the importance of vaccinations overall, inform them about missed and upcoming vaccinations. To the facilitator: Describe to the participants the rationale for IPV. The primary role of introducing one dose of IPV into routine immunization programs is to reduce risks associated with OPV withdrawal and possible reintroduction of polioviruses. The initial phase of OPV withdrawal – switch from trivalent OPV to bivalent OPV-- would lead to a gradual increase in the number of persons susceptible to type 2 poliovirus resulting in three main risks to the population. 1) Immediate time-limited risk of cVDPV2 emergence; 2) Medium and long-term risks of type 2 poliovirus re-introduction from a vaccine manufacturing site, research facility, diagnostic laboratory, or a bioterrorism event. 3) Spread of virus from rare immune deficient individuals who are chronically infected with OPV2. A reintroduction of poliovirus or cVDPV2 emergence could potentially result in a substantial polio outbreak or even re-establishment of global transmission. IPV will reduce these risks after OPV withdrawal and provide protection against polio without causing side effects. Introducing IPV to our community also helps us remind caretakers about the importance of vaccinations overall. It gives us an opportunity to review children’s routine immunization schedule and inform them about missed and upcoming vaccinations.

Key Messages Polio is a highly contagious viral disease that can spread rapidly through person-to-person contact causing permanent paralysis There are 3 types of wild poliovirus but only type 1 remains in circulation today OPV is inexpensive and effective at reducing polio transmission in developing countries, but carries a risk of VAPP and VDPV All use of OPV must stop for the world to be completely polio-free IPV is being introduced to provide protection against all 3 serotypes, while OPV is being phased out, to help us make the world polio free

Inactivated Polio Vaccine (IPV) Our country is about to introduce IPV Next modules of this training will explain how to: Store the vaccine Determine vaccine eligibility Administer the vaccine Record the vaccine dose Monitor adverse events following immunization (AEFIs) Communicate with caregivers about the vaccine To the facilitator: Introduce to the participants to the content of the training related to IPV introduction. Your country is introducing IPV. In order to ensure the best conditions for the vaccine introduction, you will be trained on how to: Store the vaccine Determine the eligibility of the vaccine Administer the vaccine Record the vaccine Monitor AEFIs Communicate with caregivers about the vaccine During the course, issues and questions will be raised and discussed in a group in order to anticipate the situations that you will be facing at the workplace. At the end of the course, you will be provided with a pocket guide on the training. The guide is intended to remind you of key information in routine practice. 16

End of module for your attention! Thank you To the facilitator: This is the end of the module. You have been introduced to the “Introduction to the polio endgame rationale and IPV vaccine ” module. The following module is titled “IPV attributes and storage conditions”. Thank you for your attention!