Nutritional status in relation to the efficacy of the rhesus-human reassortant, tetravalent rotavirus vaccine (RRV-TV) in infants from Belém, pará state, Brazil.

The rhesus-human reassortant, tetravalent rotavirus vaccine (RRV-TV) was licensed for routine use in the United States of America but it was recently withdrawn from the market because of its possible association with intussusception as an adverse event. The protective efficacy of 3 doses of RRV-TV, in its lower-titer (4 x 10(4) pfu/dose) formulation, was evaluated according to the nutritional status of infants who participated in a phase III trial in Belém, Northern Brazil. A moderate protection conferred by RRV-TV was related to weight-for-age Z-scores (WAZ) greater than -1 only, with rates of 38% (p = 0.04) and 40% (p = 0.04) for all- and- pure rotavirus diarrhoeal cases, respectively. In addition, there was a trend for greater efficacy (43%, p = 0.05) among infants reaching an height-for-age Z-score (HAZ) of > -1. Taking WAZ, HAZ and weight-for-height Z-score (WHZ) indices 0.05) if both placebo and vaccine groups are compared. There was no significant difference if rates of mixed and pure rotavirus diarrhoeal cases are compared in relation to HAZ, WAZ and weight-for-height Z-score (WHZ) indices. Although a low number of malnourished infants could be identified in the present study, our data show some evidence that malnutrition may interfere with the efficacy of rotavirus vaccines in developing countries.

Nutritional status in relation to the efficacy of the rhesus-human reassortant, tetravalent rotavirus vaccine (rrv-tv) in infants from Belém, Para state, Brazil

The rhesus-human reassortant, tetravalent rotavirus vaccine (RRV-TV) was licensed for routine use in the United States of America but it was recently withdrawn from the market because of its possible association with intussusception as an adverse event. The protective efficacy of 3 doses of RRV-TV, in its lower-titer (4 x 10(4) pfu/dose) formulation, was evaluated according to the nutritional status of infants who participated in a phase III trial in Belém, Northern Brazil. A moderate protection conferred by RRV-TV was related to weight-for-age Z-scores (WAZ) greater than -1 only, with rates of 38 percent (p = 0.04) and 40 percent (p = 0.04) for all- and- pure rotavirus diarrhoeal cases, respectively. In addition, there was a trend for greater efficacy (43 percent, p = 0.05) among infants reaching an height-for-age Z-score (HAZ) of > -1. Taking WAZ, HAZ and weight-for-height Z-score (WHZ) indices <= -1 together, there was no significant protection (p > 0.05) if both placebo and vaccine groups are compared. There was no significant difference if rates of mixed and pure rotavirus diarrhoeal cases are compared in relation to HAZ, WAZ and weight-for-height Z-score (WHZ) indices. Although a low number of malnourished infants could be identified in the present study, our data show some evidence that malnutrition may interfere with the efficacy of rotavirus vaccines in developing countries

Epidemiology of rotavirus gastroenteritis in the Amazon region and the need for a specific vaccine

In the Amazon region, rotaviruses account for at least 30 per cent of all episodes of acute gastroenteritis among hospitalized children and are associated with nearly 1O per cent of cases of infantile acute diarrhea at community level. All four rotavirus serotypes are shown to infect children in our region, serotype l being predominant (about 50 per cent). Sequential infections in the same child, caused by different serotypes, are commonly noted. No clear seasonal variation on the occurrence of rotavirus diarrhea has been recorded, as cases are readily detected throughout the year. Rotavirus diarrhea cases have been found to be, in general, more severe than those of other aetiology. On the other hand, it has been noted that early (children less than 4 months of age) rotavirus infections are more likely to be asymptomatic (p = 0.021). Occurrence of rotavirus infections among Amazonian Indian populations seems to be very common. An explosive outbreak of rotavirus diarrhea affected possibly 88 per cent of both children and adults of the Tiryió population, Northern Pará State. In addition, rotavirus antibody was detected in 54.7 per cent of 1,299 sera collected from Amerinds belonging to 13 relatively isolated communities in the Amazon region. In the light of the above mentioned findings it was suggested that our region would be suitable for a field trial with a rotavirus-candidate vaccine. A study is therefore underway aiming to compare safety, immunogenicity and efficacy of a rhesus-human reassortant rotavirus (RRV-tetravalent) vaccine and placebo in 500 healthy infants living in the peripheral area of Belém.

A possible fifth human rotavirus serotype and an unusual serotype 2, subgroup II rotavirus strains

Uma cepa de rotavírus, obtida de criança diarreica com 22 meses de idade, näo reagiu com anticorpos monoclonais para os quatro sorotipos desse agente, emergindo como um possível novo sorotipo. Essa amostra se caracterizou por pertencer ao subgrupo II, exibindo perfil genômico, por eletroforese em gel de policrilamida, tipicamente longo. Detectou-se, ainda, outra amostra de rotavírus, oriunda de criança com 19 meses de idade, assintomática, com características sorológicas que a classificaram como sorotipo 2, monoclonais. Näo se obtiveram padröes de eletroforese nucleica suficientemente nítidos, bem como näo se logrou a replicaçäo virótica dessa cepa em células da linhagem "MA 104", quer a partir da simples suspensäo de fezes, quer após efetuada a purificaçäo em gradiente de cloreto de césio. Ambos os achados acima referidos decorreram de estudo longitudinal envolvendo 88 crianças, habitantes da área periférica de Belém, observados desde o seu nascimento até os três anos de idade

Três episódios sucessivos de infecçäo por rotavírus em uma criança de Belém, Pará, Brasil / Three successive episodes of rotavirus infection in a child living in Belém, Pará, Brazil

Três episódios de infecçäo por rotavírus em uma única criança foram observados ao longo de um estudo prospectivo na área urbana de Belém, Pará, Brasil, no decorrer de seus primeiros vinte e sete meses de vida. A detecçäo do rotavírus, classificado como susbgrupo II, sorotipo näo determinado, foi obtida nas duas primeiras infecçöes, sucedendo-se uma terceira pelo subgrupo I, sorotipo 2. Nesses episódios observaram-se dois perfis eletroforéticos diferentes. A primeira infecçäo ocorreu aos 4 meses de vida e as seguintes nos 20§ e 27§ meses. Os processos infecciosos ocorreram de forma sintomática, sendo que em dois dos três episódios, as manifestaçöes clínicas foram severas; o segundo em maior grau que o primeiro e o terceiro mais benigno que os anteriores

Pattern of acquisition of rotavirus antibody in children followed up from birth to the age of three years

Nine hundred and forty-eight serum samples from 83 children living in Belem, Brazil, collected within their first three years oflife, were tested for the presence of groupspecific rotavirus-antibody by an enzyme-linked immunosorbent assay (Elisa) blocking-test. Passively transferred maternal antibody lasted about two and half months; subsenquentely, low levels of rotavirus antibody started to appear at seven months, reaching a peak at eleven months of age. From one year onwards positivity gradually increased, reaching highest values at 34 months of life. Individual responses were examined in sera from 61 children who were followed up since birth to three years of age: 38 (62,3%) of them developed a long-term immunity following first infection; eleven (18.0%) children developed a short-term immunity after first infection by rotavirus; seven (11.5%) had no antibody response within their first three years of life; and 5 (8.2%) showed positive antibody response from birth to three years old

Reinfections and Rotavirus serotypes in Belém, Brazil (preliminary report)

Infecçöes sucessivas causadas por rotavírus foram detectadas em quatro crianças habitantes de Belém, acompanhadas desde seu nascimento até os três anos de idade. Em uma delas (Reg. 23.983) três infecçöes sintomáticas foram observadas, duas por sorotipo näo especificado e outra pelo 2: a primeira aos 4 meses, a segunda aos 20, e a terceira aos 27. Outro indivíduo (Reg. 24.384) apresentou dois episódios diarréico, com intervalo de oito meses, o primeiro sorotipo 1 e o segundo por sorotipo näo identificado. Infecçöes também aparentes foram observadas em duas ocasiöes envolvendo a mesma criança (Reg. 24.004), a primeira por sorotipo 1 e, doze meses após, uma segunda pelo 2. Em uma outra criança (Reg. 24.097) duas infecçöes, ambas inaparentes e por sorotipo näo especificado, foram detectadas: a primeira aos 24 meses de vida e a segunda, aos 28