Persistence of maternal antibody in infants beyond 12 months: mechanism of measles vaccine failure.
ABSTRACT A serologic study was made in 34 children immunized against measles at the age of 12 months. Using a sensitive virus neutralization test, it was found that many of the children had pre-existing maternal antibody to measles virus. Children with high pre-existing antibody titers failed to seroconvert. Children with lower pre-existing antibody titers seroconverted, but the resulting antibody titer was significantly lower than in children without pre-existing antibody titer. The results of this study demonstrate a probably mechanism for measles vaccine failure in 12-month-old children and support the recommendation of the Public Health Service Advisory Committee on Immunization Practices to postpone measles vaccination to 15 months of age.
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ABSTRACT: Sub acute sclerosing pan encephalitis (SSPE) is a rare neurodegenerative disorder related to a persistent and aberrant measles virus infection. It is associated with poor prognosis and high mortality. We report a case of a seven- year-old boy who manifested the disease despite proper vaccination and with no documented past history of measles. The case is being reported for its atypical presentation, rarity and its possibility of occurrence in young vaccinated subjects, possibly due to undocumented pre-vaccination measles infection.Australasian Medical Journal 01/2012; 5(7):359-61.
Article: A comparison study of measles antibody between two doses vaccination at 9, 18 months and single dose at 9 months in children 4-6 years old.[show abstract] [hide abstract]
ABSTRACT: The authors have added the second dose of measles vaccine to children aged 18 months since 1997 because of the measles outbreaks in Nan province in 1993-1994. To compare measles antibody level between two doses vaccination at 9, 18 months and single dose at 9 months in children at the age of 4 to 6 years old. A cross sectional serological study in children 4 to 6 years old was performed between August 2008 and August 2009 at three hospitals in Nan and Phrae provinces. The subjects were divided into two groups, 1) 100 children in Nan provincial hospital received two doses of measles vaccination at the age of 9 and 18 months and 2) 91 children received single dose measles vaccination at the age of 9 months, 41 from Phrae provincial hospital and 50 from Weingsa district hospital. Blood samples were drawn for measles antibody measurement by ELISA assays at Virus Research Institute, National Institute of Health, Thailand. The mean measles antibody level in children 4 to 6 years old in both groups was a satisfactory high level, 1,887.67 and 1,621.02 mIU/ml in single and two doses vaccination respectively, which were not statistically significant (p = 0.431). The higher level in single dose group could be explained by the average age being younger than the two doses group by one year (4 years 2 months vs. 5 years 4 months). Therefore, the waning immunity in younger age group is suspected to be less than the older age group. The rate of protective measles antibody level (> or = 255 mIU/ml) was significantly higher in the two doses group than the single dose, 87% compared to 76% (p = 0.046), which represented primary vaccine failure at the age 4 to 6 years of 13% and 24%, respectively. The authors suggest that a second dose of measles vaccine at the age of 18 months be administered to decrease the number of primary vaccine failure from 24% to 13%. Further studies in the same age group and in different areas are required to confirm these findings.Journal of the Medical Association of Thailand = Chotmaihet thangphaet 03/2011; 94(3):309-15.
Article: Preparation Of High Potent Measles Haemagglutinating Antigen From Wild Type Measles Virus In Ibadan, Nigeria[show abstract] [hide abstract]
ABSTRACT: This study reports the preparation of preparation of high potent measles haemagglutinating antigen from wild type measles virus in Ibadan, Nigeria. Measles haemagglutinating antigen was prepared indigenously from isolates obtained from two children infected with measles at the Oluyoro Catholic Hospital (OCH) Ibadan, with titres of 7.15 and 9.5 TCID 50 . The isolates were then adapted to Vero cell line after eight serial passages. Stock isolates were then prepared in three bateches following polyethylene glycol between 80 concentration method. The haemagglutination activity (HA) of the three batches of the measles HA antigen were then tested with 4% washed monkey RBC in a 96 well V shaped bottom microtitre plate alongside with commercial measles HA antigen lot no. 733031. Batch 1 antigen gave a titre of 1:640 while commercial antigen titre was 1:320, Batch 2 antigen titre dropped one fold to give 1:320 with commercial antigen titre 1:320, and untreated measles virus gave a titre of about 1:10. Cell controls were also set up to validate the results of this study. Batch 3 HA antigen titre rose back to 1:1280 while commercial antigen gave 1:320 and untreated measles virus 1:10. Twenty-seven (27) field samples were collected from the Otunba Tuwashe Children's emergency ward (OTCHEW) of the University College Hospital (UCH), Ibadan. They were collected based on the criteria determined by past history of measles infection, vaccination history, and manifestation of other exanthematous illness. The age range of children tested was between 7 months and 15 years. An actual adult individual infected with acute measles was also tested using paired sera. All samples were tested using batch 1 antigen. The findings of the field study showed that 5 subjects with clinical history of measles tested positive to the indigenous prepared high potent measles haemagglutinating antigen with titres ranging from 1:32 to 1:128, while 6 subjects with history of vaccination had titres also ranging from 1:32 to 1:128. Four subjects with other exanthematous illness also tested positive with titres of 1:32 and 1:64. Specificity and sensitivity tests of the measles HA antigen using 4 known measles unexposed and unvaccinated subjects and 5 known measles infected subjects gave a specificity and sensitivity of 1, this showed that the antigen was highly specific and equally sensitive. The result from the adult measles patient also confirmed the efficacy of our measles HA antigen giving an acute phase serum titre of 1:16 and convalescence phase titre of 1:128, this showed a 4-fold rise in titre which is diagnostic of measles infection. The findings of this study are of a significant practical impact and confirm that an indigenous prepared antigen can give a higher titre than the commercially prepared antigens. Thus, if the indigenous prepared antigen is further refined and produced massively, it will be highly cost effective especially in field for sero-monitoring and surveillance. [Motayo Babatunde O, Okonko Iheanyi O, Faneye Adedayo and Adu Festus D.NEW YORK SCIENCE JOURNAL. 12/2011;