ADEIGA.A, AWODERU O.A,FANEYE.A, AKINTUNDE, GB, ONYEWUCHE.J. SERUM LEVELS OF Th1 and Th2 CYTOKINES PRODUCED IN NIGERIAN CHILDREN WITH MEASLES VACCINE FAILURE IN MEASLES OUTBREAK IN OGUN STATE IN NIGERIA BY ADEIGA.A, AWODERU O.A,FANEYE.A, AKINTUNDE, GB, ONYEWUCHE.J. 16TH ANNUAL INTERNATIONAL CONFERENCE ON VACCINE RESEARCH AT HOTEL HAYYAT BALTIMORE MARYLAND USA 20TH -22ND APRIL 2013.

OUTLINE Background Statement of Problem Aim Objectives Materials and Methods Result Discussion

BACKGROUND Low routine measles vaccination coverage is frequently reported in Nigeria(Okonko et al 2009). Also quality of mass measles immunization campaign is not high enough to contain measles outbreak. This makes outbreak of measles to continue to occur in highly vaccinated population(Okonko et al 2009). Occurrence of measles infection in vaccinated children is an indication of vaccine failure.

BACKGROUND Two types of vaccine failure. -primary - lack of antibody after immunization. - secondary- waning of immunity with age or insufficient antibody after immunization. Report of measles in vaccinated children exhibit reduced severity, mild clinical symptoms which mostly occur in older children who have history of measles immunization but with waning immunity with age. In this study we examined the pathogenesis of measles infection in vaccine failure situation with respect to pro and anti inflammatory cytokines and associated clinical presentations.

PROBLEM STATEMENT Children vaccinated against measles get infected during measles outbreak. This is evidence of measles vaccine failure. There is need to evaluate the degree of pathogenesis of measles infection in such children with respect to inflammatory responses which literature has reported to have caused irreversible damages such as osteosclerosis.

AIM AND OBJECTIVES AIM: To evaluate effect of vaccine on pathogenesis of measles infection in vaccinated children. OBJECTIVES: - Determine mild and severe measles infection in vaccinated children by the clinical presentation. -Establish state of IgM and IgG in the vaccinated children -Assess the Th1/Th2 cytokines in vaccinated children in a state of vaccine failure.

METHODS Study Population: -Sixty five children within age 6 months to 11years reported to be infected with measles in an outbreak and 37 healthy children were assessed as control. Study site: -The children were admitted to primary health care centers during measles epidemic outbreak in eight local government areas of Ogun State.

METHOD CONTD Sample Collection: Blood samples were collected in plain bottles at the health centers where the children were admitted and questionnaires were administered to get the demography, vaccination history and clinical symptoms. Blood samples from age and sex marched healthy children were used as control. Serum samples used for the Immuno assay were separated from blood by centrifugation. Ethical approval was obtained from NIMR-IRB.

METHOD CONTD. Antibody Assay: Measles IgM and IgG antibodies were evaluated to determine infection and protection respectively. This was done by ELISA technique following manufacturer’s procedure. Assay of the Cytokines: Four cytokines IL-1β, IL-12,TNF-α and TGF-β were assayed. The serum cytokines were measured in duplicate using ELISA test kit. The manufacturer’s instructions were strictly followed. Range values of the cytokines measured were IL-1β (1ng/ml-20ng/ml), IL-12 (3ng/ml-90ng/ml), TNF-α (20ng/ml-400ng/ml) and TGF-β (50ng/ml-1500ng/ml).

RESULT Table 1 Demographic characteristics of children infected with measles and of healthy control. CHARACTERISTICS HEALTHY CONTROL CHILDREN INFECTED WITH MEASLES GENDER MALE no (%) 22 (59.5) 31 (47.7) FEMALE no (%) 15 (40.5) 34 (52.3) AGE MEAN 6.92 3.17 RANGE 10 (3-13) 10.94 (6 mth-11 yrs

TABLE 2. DISTRIBUTION OF MAJOR SIGNS AND SYMPTOMS OF MEASLES OBSERVED IN INFECTED CHILDREN. SYMPTOMS/SIGNS NUMBER PERCENTAGE (%) FEVER 65 100 RASH COUGH 18 27.7 CORYZA 52 80 CONJUCTIVITIS 62 95.6 BRONCHOPNEOMONIA 47 72 KOPLIK SPOT

TABLE 3. DISTRIBUTION OF MEASLES INFECTION IN RELATION TO AGE. NUMBER POSITIVE FOR MEASLES INFECTION NEGATIVE FOR MEASLES INFECTION 0-2yrs 30 22 (73.3%) 8 (26.7%) >2-4 yrs 35 22 (62.9%) 13 (37.1%) >4-6 yrs 20 15 (75%) 5 (25%) >6-8 yrs 7 3 (42.9%) 4 (57.1%) >8 yrs 10 3 (30%) 7 (70%)

TABLE 4. DEGREE OF INFECTION RELATIVE TO AGE

TABLE 5. DISTRIBUTION OF VACCINATION STATUS OF CHILDREN STUDIED AGE NUMBER VACCINATED UNVACCINATED <2 yrs 30 14 (46.7%) 16 (53.3%) < 5 yrs 55 35 ( 63.6%) 20 (36.4%) >5 yrs 17 12 (70.6 %) 5 (29.4 %)

TABLE 6. DISTRIBUTION OF MEASLES INFECTION IN RELATION TO VACCINATION STATUS. MEASLES INFECTED CHILDREN NON INFECTED CHILDREN VACCINATED 31 30 NON VACCINATED 34 7

DISCUSSION We observed in this study children under five years to have suffered more severe infection. This included both the vaccinated and unvaccinated. The issue of concern is the ineffectiveness of measles vaccine to contain the infection. The IgG antibody generated from vaccination was not protective enough to neutralise the infection. This was reflected in the inflammatory cytokines generated from the measles infection. It was observed that the magnitude of the cytokines was not different from the unvaccinated children.

DISCUSSION This observation is only expected in children above five years which measles immunity is expected to wane with age. This observation is questioning the integrity of the measles vaccine or the cofounding factors of immunity in the children. These factors mentioned above could be as the limitation of this study. This could have elucidated the details hindering the effective immune response expected in the children vaccinated.

RECOMMENDATION Children must be vaccinated against measles with good quality vaccine. Cold-chain preservation of the measles vaccine must be of high standard so as to ensure high potency of measles vaccine used.

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