1. Epidemiology of Measles Prof. Ashry Gad Mohamed Prof. of Epidemiology

2.  Highly contagious viral illness  First described in 7th century  Near universal infection of childhood in prevaccination era  Common and often fatal in developing areas

3. No second opportunity for measles immunization ( 45 ) 94 % of all measles deaths in 2000 Leading killer of children We know WHERE...

4. Cases 2005 . An estimated 345 000 people, the majority of them children, died from measles in 2005.  From 2000 to 2005, more than 360 million children globally received measles vaccine. 

5. Global Progress Measles Mortality Reduction by 50% by 2005 (compared to 1999 : 875,000 deaths) Estimated Measles Mortality by Year

6. Deaths from Measles  Africa 126 000 [93 000 - 164 000]  Americas <1 000 [-]  Eastern Mediterranean 39 000 [26 000 - 53 000]  European <1 000 [-]  South-East Asia 174 000 [126 000 - 233 000]  Western Pacific 5000 [3000 - 8000]  TOTAL 345 000 [247 000 - 458 000]

7. Measles Mortality Reduction in EMRO Region, 1999-2004 EMRO

8. Libya Egypt Sudan Morocco Tunisia Somalia Saudi Arabia Yemen Oman Djibouti Pakistan Afghanistan Iran Iraq Syria Jordan Lebanon Palestine Qatar UAEBahrain Kuwait

9. Percent reduction in estimated measles deaths by WHO region between 1999 and 2002

10. Measles Case Counts and Coverage Saudi Arabia 1983-2004

11.  There was a marked reduction in the epidemic peak from 500/100 000 in the 1970s to < 80/100 000 in the 1990s.  Incidence among children 6–8 months of age fell from > 400/100 000 before the implementation of the new policy to 200/100 000 before the implementation of the new policy to 400/100 000 before the implementation of the new policy to 200/100 000 before the implementation of the new policy to <100/100 000 in 1997.  2005 373cases

12. Measles Pathogenesis  Respiratory transmission of virus  Replication in nasopharynx and regional lymph nodes  Primary viremia 2-3 days after exposure  Secondary viremia 5-7 days after exposure with spread to tissues

13. Measles Clinical Features  Incubation period 10-12 days  Stepwise increase in fever to 103°F or higher  Cough, coryza, conjunctivitis, malaise, sneezing, rhinitis, congestion  Koplik spots Prodrome

14. Koplik's spots, are pathognomonic in measles, appear on the buccal and lower labial mucosa opposite the lower molars as White spots inside the mouth

15. Measles Clinical Features  2-4 days after prodrome, 14 days after exposure  Maculopapular, becomes confluent  Begins on face and head  Persists 5-6 days  Fades in order of appearance Rash

16. Child has a rash caused by measles

17. Measles rash covering child's arms and stomach

18. ConditionDiarrhea Otitis media PneumoniaEncephalitisHospitalizationDeath Percent reported 8 7 6 0.1 18 0.2 Measles Complications Based on 1985-1992 surveillance data

19. Measles Complications by Age Group

20. Measles Clinical Case Definition  Generalized rash lasting >3 days, and  Temperature 101°F (>38.3°C), and  Cough or coryza or conjunctivitis

21. Measles Laboratory Diagnosis  Isolation of measles virus from a clinical specimen (e.g., nasopharynx, urine)  Significant rise in measles IgG by any standard serologic assay (e.g., EIA, HA)  Positive serologic test for measles IgM antibody

22. Measles Virus  Paramyxovirus (RNA)  One antigenic type  Rapidly inactivated by heat and light

23. Reservoir  Human Incubation period. Clinical case Clinical case  No animal reservoir

24. Transmission  The virus spreads by the respiratory route via aerosol droplets and respiratory secretions which can remain infectious for several hours.  The infection is acquired through the upper respiratory tract or conjunctiva

25.  In the pre-vaccination era, the maximum incidence was seen in children aged 5 - 9 years. By the age of 20, approximately 99% of subjects have been exposed to the virus.  With the introduction of vaccine, measles infection has shifted to the teens in countries with an efficient programme.

26.  In contrast, in third world countries, measles infection has its greatest incidence in children under 2 years of age.  the disease is a serious problem with a high mortality (10%) with malnutrition being an important factor in developing countries  In general measles mortality is highest in children < 2 years and in adults

27.  Temporal pattern Peak in late winter–spring  Communicability 4 days before to 4 days after rash onset.

28. Strategy for sustainable measles mortality reduction 1. Strong routine immunization > 90% Reaching Every District Strategy Reaching Every District Strategy 3. Surveillance 2. Provide second opportunity for measles immunization One time only “catch-up” campaign ( < 15 ) One time only “catch-up” campaign ( < 15 ) “Follow-up” campaigns every 3-4 years ( < 5 ) “Follow-up” campaigns every 3-4 years ( < 5 ) Routine scheduled second dose / opportunity Routine scheduled second dose / opportunity 4. Improved case management

29. Palestine Bahrain Measles Campaigns in EMRO through 2005 Preschool and school age (13) School age (5) Preschool age (1) Not done (1) Ongoing (2)

30. 1963Live attenuated and killed vaccines 1965Live further attenuated vaccine 1967Killed vaccine withdrawn 1968Live further attenuated vaccine (Edmonston-Enders strain) 1971Licensure of combined measles- mumps-rubella vaccine 1989Two dose schedule 2005Licensure of MMRV Measles Vaccines

31. Measles Vaccine  CompositionLive virus  Efficacy95% (range, 90%-98%)  Duration of ImmunityLifelong  Schedule2 doses  Should be administered with mumps and rubella as MMR  The seroconversion rate is 95% and the immunity lasts for at least 10 years or more, possibly lifelong

32. MMRV (ProQuad)  Combination measles, mumps, rubella and varicella vaccine  Approved children 12 months through 12 years of age (up to age 13 years)  Titer of varicella vaccine virus in MMRV is more than 7 times higher than standard varicella vaccine

33. MMR Vaccine Failure  Measles, mumps, or rubella disease (or lack of immunity) in a previously vaccinated person  2%-5% of recipients do not respond to the first dose  Caused by antibody, damaged vaccine, record errors  Most persons with vaccine failure will respond to second dose

34. Measles (MMR) Vaccine Indications  All infants >12 months of age  Susceptible adolescents and adults without documented evidence of immunity

35. Measles Mumps Rubella Vaccine  12 months is the recommended and minimum age  MMR given before 12 months should not be counted as a valid dose  Revaccinate at >12 months of age

36. Second Dose of Measles Vaccine  Intended to produce measles immunity in persons who failed to respond to the first dose (primary vaccine failure)  May boost antibody titers in some persons

37. Second Dose Recommendation  First dose of MMR at 12-15 months  Second dose of MMR at 4-6 years  Second dose may be given any time >4 weeks after the first dose

38. MMR Adverse Reactions  Fever5%-15%  Rash5%  Joint symptoms 25%  Thrombocytopenia<1/30,000 doses  Parotitis rare  Deafness rare  Encephalopathy <1/1,000,000 doses

39. MMR Vaccine and Autism  Measles vaccine connection first suggested by British gastroenterologist  Diagnosis of autism often made in second year of life  Multiple studies have shown no association

40. MMR Vaccine and Autism “The evidence favors a rejection of a causal relationship at the population level between MMR vaccine and autism spectrum disorders (ASD).” “The evidence favors a rejection of a causal relationship at the population level between MMR vaccine and autism spectrum disorders (ASD).” - Institute of Medicine, April 2001 - Institute of Medicine, April 2001

41. MMR Vaccine Contraindications and Precautions  Severe allergic reaction to vaccine component or following prior dose  Pregnancy  Immunosuppression  Moderate or severe acute illness  Recent blood product

42.  The use of live-attenuated vaccine for post- exposure prophylaxis is contraindicated.