Polio

polio disease, prevention strategies, Pulse polio Immunization, AFP surveilance

1. POLIO -by Dr. Sudhir

2. History Sir Walter Scott(1771–1832) may have had the earliest recorded case of polio. First described by Michael Underwood in 1789 Initially thought to be due to trauma Became known as the Heine-Medin disease due to the work of Dr. Jakob Heine and Dr. Karl Oskar Medin. Later called infantile paralysis, based on its propensity to affect children. 3 rd human disease targeted for eradication

3. Poliovirus Enterovirus Spherical virion with a single strand RNA Three serotypes: 1, 2, 3 Burnhilde & Mahoney strains → type1 Lansing & MEF-1 → type 2 Leon & Saukett → type 3 1 & 3 – epidemic 2 – endemic Minimal heterotypic immunity between serotypes

4. ANTIGENS D or Native or N antigen - whole virion & is type specific - Anti-D antibody is protective and its conc in IPV denotes the potency of vaccine C or Heated or H antigen - empty non-infectious virus & is less specific - anti-C antibody does not neutralise infectivity Heated at 56 º C - D →→→ C

5. Resistance Resistant to ether, chloroform, bile, intestinal proteolytic enzymes & detergents Stable at pH of 3 Can survive at -20 º C for yrs, 4 º C for months & at room temp for 1 day to several weeks Inactivated by heat(55 º C for 30 min) , formaldehyde, ultraviolet light & chlorination Organic matter in water delays the activation by chlorination

6. Pathogenesis Entry by feco-oral route through ingestion Droplets from Patients with early disease can enter through inhalation or through conjunctiva Replication in the epithelial cells of GI tract & the local lymphatics

7. Local lymhatics of GIT ↓ Circulatory system (minor or primary viremia) ↓ Reticuloendothelial system ↓ Circulatory system (major or secondary viremia) ↓ Spinal cord & Brain

8. NERVOUS SYSTEM CNS – Multiplies in Neurons & destroys them Earliest change – Degeneration of Nissl bodies Followed by Nuclear changes & finally neuronal death Spinal cord – Lesions are mostly in the ant. Horns causing flaccid paralysis Post. Horn & intermediate column may also be involved

9. 90 to 95% polio virus infections are asymptomatic Outcomes of Poliovirus Infection

10. Poliovirus Epidemiology Reservoir Human Transmission Fecal-oral Oral-oral possible Communicability 7-10 days before or after onset . Virus present in stool 3-6 weeks

11. Types • Asymptomatic Polio • Non-paralytic • Paralytic – Spinal – Bulbar – Bulbospinal

12. Asymptomatic Polio • Accounts for approximately 95% of cases • Virus stays in intestinal tract and does not attack the nerves • Virus is shed in the stool so infected individual is still able to infect others

13. Non-paralytic Polio •Abortive poliomyelitis •Does not lead to paralysis •Mild symptoms seen such as sore throat, fever, n/v, diarrhea, constipation ( Minor illness) •Most recover in <1 week •Non-paralytic aseptic meningitis ( Major illness) – Occurs in 1-2% of polio infections – Symptoms are stiffness in the neck, back, and/or legs – Increased or abnormal sensations can occur – Complete recovery after 2-10 days of symptoms

14. Paralytic Polio Fewer than 1% of those infected develop this type Acute flaccid paralysis seen. Initially focal but spreads over 3 – 4 days Headache, neck/back stiffness, unusual sensations, increased sensitivity to touch Tripod sign + Descending paralysis Asymmetrical patchy paralysis Deep tendon reflex lost before onset of paralysis

15. Spinal Polio –Most common form of paralytic; 79% –Attacks motor neurons and causes paralysis of muscles of respiration and muscles of extremities –Children <5 years most likely to become paralyzed in one leg –Adults are most commonly paralyzed in both arms and legs –Those affected still retain sensation in extremities

16. Bulbar Polio • Accounts for 2% of paralytic polio • Virus attacks motor neurons in brainstem •Affects cranial nerve function •Primarily inhibits ability to breathe, speak, and swallow effectively Facial asymmetry present

17. Bulbospinal Polio • Accounts for 19% of paralytic cases • Affects extremities and cranial nerves • Leads to severe respiratory involvement

18. Paralytic Polio Risk Factors • Compromised immune system • Pregnancy • Mouth or throat surgery • Injury or strenuous physical exercise after exposure to virus

19. Encephalitic Polio •Very rare •Causes inflammation of gray matter of brain •Signs/symptoms include agitation, confusion, stupor, and coma •Autonomic dysfunction is common and it has a high mortality

20. Past Medical Treatment • Iron Lung - a sealed chamber with an electrically driven bellows that regulates breathing. • Rigid Braces • Body Casts

21. Supportive Treatment • Antibiotics for infection • Analgesics for pain • Portable Ventilators for breathing problem • Moderate Exercise • Nutritional Diet

22. Post-Polio syndrome (PPS) 25 % of individuals, decades after recovering from the acute infection Features include muscle weakness, extreme fatigue, or paralysis. Due to failure of the over-sized motor units created during recovery from paralytic disease Factors that increase the risk of PPS include time since acute poliovirus infection,permanent residual impairment, and both overuse and disuse of neurons

23. PREVENTION

24. Global Polio Eradication Initiative launched in 1988 Polio cases have decreased by over 99% since 1988, from an estimated 350 000 cases then, to 1604 reported cases in 2009. In 2010, only four countries in the world remain polio-endemic, down from more than 125 in 1988. The remaining countries are Afghanistan, India, Nigeria and Pakistan

25. Wild Poliovirus 1988

26. Wild Poliovirus 2002

27. Wild Poliovirus 2012

28. Wild Poliovirus 2014

29. 1. High infant immunization coverage with four doses of oral poliovirus vaccine (OPV) in the first year of life 2. Supplementary doses of OPV to all children under five years of age during SIAs(PPI) 3.AFP surveillance among children under fifteen years of age; 4. Targeted “mop-up” campaigns once wild poliovirus transmission is limited to a specific focal area. Core strategies of GPEI

30. Poliovirus Vaccine 1955 Inactivated vaccine 1961 Types 1 and 2 monovalent OPV 1962 Type 3 monovalent OPV 1963 Trivalent OPV 1987 Enhanced-potency IPV (IPV)

31. Inactivated Polio Vaccine Developed in 1952 by Jonas Salk Contains 3 serotypes of vaccine virus 40 units of 1(Mahoney), 8 units of 2(MEF-1) & 32 units of 3(Saukett) Grown on monkey kidney (Vero) cells Inactivated with formaldehyde Contains trace 2-phenoxyethanol, neomycin, streptomycin, polymyxin B Safe in immunocompromised & in pregnancy

32. Inactivated Polio Vaccine Heat stable at room temp but should be refrigerated to preserve potency Highly effective in producing immunity to poliovirus >90% immune after 2 doses >99% immune after 3 doses Humoral immunity and to some extend pharyngeal immunity Duration of immunity not known with certainty

33. Oral Polio Vaccine Discovered by Albert Sabin Contains 3 serotypes of vaccine virus 3 lakh TCID 50 of type 1 1 lakh TCID 50 of type 2 3 lakh TCID 50 of type 3 Grown on monkey kidney (Vero) cells Contains neomycin and streptomycin Shed in stool for up to 6 weeks following vaccination

34. Oral Polio Vaccine Produces both Humoral & local immunity Contributes to herd immunity 50% immune after 1 dose >95% immune after 3 doses Immunity probably lifelong Heat labile: -20 º C Can be stabilised by adding MgCl Should not be frozen & thawed repeatedly

35. Polio Vaccine Adverse Reactions Rare local reactions (IPV) No serious reactions to IPV have been documented Paralytic poliomyelitis (OPV)

36. Polio Vaccine Contraindications and Precautions Severe allergic reaction to a vaccine component or following a prior dose of vaccine Moderate or severe acute illness

37. Vaccine-Associated Paralytic Polio Mutation of the vaccine inside the body may case lose of attenuation(itself brought on by reversion) leads to paralytic polio Increased risk in persons > 18 years & those with immunodeficiency ( B cell) No procedure available for identifying persons at risk of paralytic disease 5-10 cases per year with exclusive use of OPV

38. 2005 in India: Wild case: 66; VAPP 180 Many countries switched to sequential IPV-OPV and then only IPV schedules once the number of VAPP cases exceeded wild polio cases.

39. Vaccine-Derived Paralytic Polio virus These viruses like those causing VAPP are neurovirulent but additionally are transmissible and capable of causing outbreaks. They have been classified into three groups; circulating VDPV (cVDPV), VDPV in the immuno-deficient (iVDPV) and VDPV of ambiguous origin (aVDPV). Risk factors for outbreaks due to cVDPV include dropping immunization coverage (both routine and SIA's), high population densities, tropical conditions and previous eradication of wild virus

40. POLIO & ITS PREVENTION IN INDIA

41. India is one of the four countries with wild polio virus Most cases are reported from Bihar & UP Cases seen in various states of north india are due to import from there 2 states 2010 – 42 cases Last case of type 2 in 1999 Last WPV3 Oct 2010 Last WPV1 Jan 2011 Polio free country – Jan 2014

42. Polio Vaccination under UIP Vaccine OPV º OPV1 OPV2 OPV3 OPV4 Age birth 6 wks 10 wks 14 wks 16-24 Months

43. Two drops of OPV is used Nose should not be pinched Instead apply pressure to both side of mouth Breast feeding is not contraindicated Hot liquids to be avoided for ½ hr after OPV

44. Pulse Polio Immunization (PPI) The supplementary immunization activities (SIAs) in India launched in 1995 Irrespective of the immunisation status Usually Dec & Jan – Peak transmission

45. Providing additional OPV doses to every child aged <5 years at intervals of 4-6 weeks during National Immunization Days (NIDs) & sub-National Immunization Days (SNID's) It “Flood” the community with OPV within a very short period of time, thereby interrupting transmission of virus throughout the community. Intensification - house-to-house “search and vaccinate” component. The number of PPI rounds is determined by the extent of poliovirus transmission in the country.

46. Cold Chain The system of transporting, storing and distributing vaccine in a potent state at recommended temperature till it is administered to an individual. If cold chain is not maintained from the manufacturer to the place of vaccination, the vaccine efficacy greatly suffers Most vaccines lose their potency by heat and sunlight and hence need protection from both(2).

47. The Cold Chain Equipment (a) Walk in cold rooms: 3 months and serve districts. (b) Deep freezers (300 ltr) and Ice lined Refrigerators : Deep freezers are used for making ice packs and to store OPV and measles vaccines. (c) Small deep freezers and ILR (140 ltr) (d) Cold boxes: peripheral centers.mainly for transportation. (e) Vaccine carriers:Used to carry small quantities of vaccines (16-20 vials) for the out of reach sessions. (f) Ice packs

48. Vaccine Vial Monitoring The vaccine vial monitor is a small thermochromic sticker on the vaccine vial and changes color as the vaccine is exposed to heat. The color of the sticker tells whether the vaccine must be discarded due to excessive heat exposure. It reduces uncertainty and waste.

49. AFP Survillance Acute flaccid paralysis is defined as: Any case of AFP in a child aged <15 years, or any case of paralytic illness in a person of any age when polio is suspected. All health facilities, clinicians and other practitioners are required to notify AFP cases immediately to the DIO, by the fastest means available

50. Sample Collection Two stool specimens are collected as soon as possible after the onset of paralysis in the child – ideally within 14 days of onset of paralysis and at least 24 hours apart. Specimens collected within 14 days are much more likely to yield the virus. Each specimen should be 8 grams – each about the size of one adult thumb – collected in a clean, dry, screw-capped container. The container need not be sterile and no preservative/transport media should be used.

51. Reverse Cold Chain The specimens are transported in the “cold chain” – on frozen ice packs or ice, in a stool specimen carrier or a vaccine carrier specifically designated for this purpose – to one of India’s eight WHO-accredited polio laboratories. Indicator of the quality of the “reverse cold chain” ↓ % of Stool specimens from which a non-polio enterovirus is isolated → ≥ 10 (i.e. that the specimen has been continuously maintained at temperatures <8° C during transportation from the field to the laboratory)

52. 60-day follow-up examination: To confirm the presence or absence of residual weakness. A 60-day follow-up exam if 1) inadequate or no stool specimens 2) isolation of vaccine virus from the stool 3) isolation of wild poliovirus from the stool 4) strongly suggestive of poliomyelitis on initial examination (“hot case”). The child is assessed for weakness, asymmetrical skin folds, and difference in left/right mid-arm/mid-thigh circumference. The child is considered to have residual weakness if any of the above is present, even if minimal. The finding of residual weakness taken into account during final case classification

53. Classification

54. Outbreak response immunization (ORI) House-to-house immunization following the AFP case investigation and stool specimen collection Children aged 0-59 months are given one dose of oral poliovirus vaccine (OPV) regardless of the number of doses received previously. The recipients include children of the target age group in the village/locality of the AFP case. The investigation team searches for additional AFP cases in the community, which – if present – could signal the possibility of a polio outbreak.

55. Active case search Where an AFP case resides – or where an AFP case has visited during the incubation period for polio (4-25 days before paralysis onset) Carried out immediately along with ORI. A search is conducted for any children aged <15 years who have had the onset of flaccid paralysis within the preceding 60 days. All cases that are found are investigated immediately, with collection of two stool specimens before administration of OPV.

56. “Mopping-up” immunization Started when poliovirus transmission has been reduced to well-defined and focal geographic areas. Intensive house-to-house, child-to-child immunization campaigns are conducted over a period of days to break the final chains of virus transmission.

57. THANK YOU