Presentation on theme: "Module 1 Introduction to the polio endgame rationale and IPV vaccine"— Presentation transcript:
1 Module 1 Introduction to the polio endgame rationale and IPV vaccine Training for Inactivated Poliovirus Vaccine (IPV) introductionModule 1Introduction to the polio endgame rationale and IPV vaccine
2 Learning objectivesAt the end of the module, the participant will be able to:Understand poliovirus transmission, poliomyelitis disease and global progress toward polio eradicationRecognize the vaccines available against polio and the risks and benefits of eachDescribe the rationale for introducing IPV into the routine immunization scheduleDuration20 minutes
3 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?3What is the status of polio eradication globally?4To 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
4 What is polio disease?Polio (also called Poliomyelitis) is a highly infectious disease caused by a virusThe virus invades the nervous system and can cause permanent paralysisPolio is spread through person-to-person contact and can spread rapidly through a communityMost infected people (90%) have no symptoms or very mild symptomsHowever, one in 200 infections leads to permanent paralysis (can’t move parts of the body) and even deathTo 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.
5 How does poliovirus spread? Poliovirus infection is highly contagiousPoliovirus is spread mostly by the fecal-oral routePrimary mode of transmission – passage of the virus in stool to the mouth of another childCan also be spread through saliva or droplets from a sneeze or coughTo 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 transmissionTransmission is especially high in situations of crowding and poor hygiene and sanitation.Child excretes virus in stoolVirus transferred to objects from handsVirus transferred to another child’s handsVirus transferred ingestedNext cycle of infection
6 How many polio cases are there? 1988350,000 cases125 endemic countriesWorld Health Assembly resolved to eradicate polio2013416 cases reported (as of 14 May 2014)3 endemic countries7 countries with re-established transmissionTo 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 worldwideSecond, 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
7 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 1999Type 3 – last case reported in 2012 (more time is needed to certify eradication)To the facilitator:Explain to the participants the types of poliovirusesPolioviruses 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.
8 Types of Oral Polio Vaccines Trivalent OPV (tOPV): types 1, 2 and 3most commonly used OPV in routine immunization globallyBivalent OPV (bOPV): types 1 and 3commonly used in supplementary immunization activities (SIAs)Monovalent OPV (mOPV): type 1, 2 or 3primarily used for SIAs in areas where only type 1 or type 3 is circulatingOPV is still the primary vaccine for eradication
9 Paralysis associated with OPV OPV offers effective protection against polio, but…In very rare cases it can lead to paralysisVaccine Associated Paralytic Polio (VAPP)Vaccine virus spontaneously changes and becomes capable of causing disease to the nervous system1 case per 2.4 million vaccine doses administeredcases/year40% of VAPP are from type 2 OPVCirculating 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 polio97% of cVDPVs are from type 2 OPVLow coverage is one of the main factors for the occurrence of cVDPVsTo the facilitator:Explain to the participants about the risks of OPVAlthough 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.
10 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 casesAlthough 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 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 duringPost-interruption of WPV transmission* as of 21 May 2014
11 Polio eradication plan In May 2012 the World Health Assembly of WHO declared poliovirus eradication to be a global public health emergencyUnder this plan to achieve a polio-free world, they recommend that the use of OPV must eventually be stopped worldwideType 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 useOPV will be withdrawn in 2 phases beginning with type 2 OPVTo the facilitator:Explain to the participants the Polio eradicationBecause 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 bOPVPhase 2: withdrawal of bOPV after the certification of eradication of wild poliovirusesThe phased withdrawal of OPV related to the epidemiology of WPV and vaccine-related cases of polio occurring globally in the past decade.
12 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 withdrawnRationale for this includes:To reduce risks of an outbreak after type 2 OPV vaccine withdrawalTo help stop outbreaks quickly if type 2 virus is reintroducedTo boost immunity against polio types 1 & 3 to protect populations and hasten eradicationSAGE 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:
13 Comparison of OPV and IPV? Oral polio vaccine (OPV)Inactivated polio vaccine (IPV)Live, attenuated (weakened) virusAdministered by dropsHighly successful in reducing transmission in developing countries as part of eradication strategyInexpensiveEasy to administerProvides mucosal/gut immunityProtects close contacts who are unvaccinatedKilled virusAdministered by injectionHighly effectiveUsed commonly in developed countriesMore expensive than OPVRequires trained health workersProvides immunity through bloodCarries no risk of VAPP or VDPVBoth vaccines are needed to fully eradicate polio!To the facilitatorExplain 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 virusInactivated Polio Vaccine (IPV) is a Killed virus administered by injectionBoth 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.
14 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 achievedWhen use of OPV is eventually stopped, IPV will continue to provide full protectionIntroducing 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.
15 Key MessagesPolio is a highly contagious viral disease that can spread rapidly through person-to-person contact causing permanent paralysisThere are 3 types of wild poliovirus but only type 1 remains in circulation todayOPV is inexpensive and effective at reducing polio transmission in developing countries, but carries a risk of VAPP and VDPVAll use of OPV must stop for the world to be completely polio-freeIPV is being introduced to provide protection against all 3 serotypes, while OPV is being phased out, to help us make the world polio free
16 Inactivated Polio Vaccine (IPV) Our country is about to introduce IPVNext modules of this training will explain how to:Store the vaccineDetermine vaccine eligibilityAdminister the vaccineRecord the vaccine doseMonitor adverse events following immunization (AEFIs)Communicate with caregivers about the vaccineTo 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 vaccineDetermine the eligibility of the vaccineAdminister the vaccineRecord the vaccineMonitor AEFIsCommunicate with caregivers about the vaccineDuring 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
17 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!