Seroconversion of children following natural measles infection and vaccination.

OBJECTIVE: To evaluate the relationship between measles virus (MV) antibodies (abs) in sera and breast milk of nursing mothers, their contributions in seroconversion of children (0-9 months) post vaccination, prevalence of prevaccination measles abs in sera of children brought for measles vaccination and seroconversion rate in vaccinees from nursing and lactating mothers. Also to determine the potency of vaccines available in Nigeria in relation to seroconversion. METHODS: One hundred and twenty pre- and post-vaccination sera and breast milk samples were collected from each nursing mother while corresponding number of finger prick pre- and post-vaccination sera samples were collected from children on filter papers. These were tested for mv abs using serological techniques. RESULTS: Eighty (20.0%) mothers had measles haemagglutination inhibition (HI) abs in sera and 88 (27.2%) had mv HI abs in breast milk. Eight (2.0%) children who had prevaccination mv abs in sera came from mv ab negative mothers. Forty-four (37.0%) came back for post vaccination sera, sero-converted while 76 (63.3%) gave low sero-conversion rate of 37.0%. Results showed that mv abs in sera or breast milk of mothers did not interfere with mv vaccination in children. The low sero-conversion rate obtained was due to low vaccine potency with titres ranging between (log10-10 - log10-2.5)TCID/per dose, besides non-specific antiviral substances exhibited virus neutralizing activity. CONCLUSION: Poor sero-conversion due to loss of passive immunity arose from undernourishment while low ab titres came with natural infection. This suggested mv vaccination did not immunize following natural mv infection or any other previous immune status.

Human immunodeficiency virus type-1 (HIV-1) and the associated clinical features among sero-positive Nigerian subjects.

Enzyme Linked Immunosorbent Assay (ELISA) and Westernblot were employed to analyze sera collected from one thousand and fifty (1050) patients who tested HIV positive type-1. Out of this, 95 (9.1%) of the patients were less than 2 years old, 102 (10.0%) were aged between 2-15 years old while 813 (77.4%) were aged above 15 years. For any age group, the ratio of male to female was 1:1 except that there was excess of males below 5 years. There were four (4) most frequent signs and symptoms observed. These were loss of weight or malnutrition, generalized lymphadenopathy, chronic watery diarrhoea and chronic chest infections. Loss of weight was recorded in 65.0% of the seropositive patients in all age groups. Generalized lymphadenopathy was seen in 35.0% of all the age groups but was most frequent in 36.1% of those less than 2 years. Chronic watery diarrhoea (42.8%) was frequent in patients less than 2 years and less frequent in 18.0% of older children between 1-15 years. Chronic chest infections were least frequent in 25.0% of adults above 15 years old and highest frequency was observed in 53.0%, children less than 2 years. Forty patients had incomplete documentations and children of pediatric ages had acutely overt clinical manifestation of HIV (1&11) attributable to undeveloped immune competence.