 |
|
Brief Reports Indian Pediatrics 2001; 38: 267-271 |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Seropositivity Rate for HIV Infection in Hospitalized Children on Selective Screening |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Though the first seropositive infant was detected as early as in 1987(1), in India children are usually considered at the periphery of Acquired Immunodeficiency Syndrome (AIDS) pandemic. However, despite frequent under-reporting, 4% of total AIDS cases in India till 1996 were below 14 years of age(2). In Mumbai, a city with the highest prevalence of adult Human Immuno-deficiency Virus (HIV) infection in India, around 2.5% to 4.2% of antenatal mothers were found to be seropositive recently(3,4). The study hospital is located near a large commercial sex area, where nearly half of the workers are infected(3,4). The present analysis was conducted to detect the seropositive rate (SPR) for HIV infection in hospitalized children, and to assess the usefulness of screening on the grounds of clinical suspicion in detection of new cases.
The present study includes prospectively collected data in two phase (1992-1994 and 1997-1998) and information obtained on review of case records for the years 1995-1996. During this period, hospitalized children of pediatric wards who had history of high risk exposure and/or clinical features suggestive of symptomatic HIV infection(5) were screened for HIV infection, using an ELISA test (Innogenetics, Belgium or Labsystem OY, Finland). Many cases fulfilling these criteria could not be screened due to refusal of consent or shortage of diagnostic kits. Newborns born to seropositive mothers in our hospital were also excluded. All ELISA reactive cases, were subjected to a second ELISA or a rapid test (HIV- Spot; Genelabs diagnostics, Geneva or Immunocomb II; Organics, Israel) as Western blot testing was not feasible in many of them due to financial constraints. As per World Health Organization (WHO), a combination of ELISA and/or simple rapid test may be used for the surveillance in developing countries(6). All children above 18 months with double test positive were considered ‘seropositive’. However, younger children were labeled as seropositive only if they also fulfilled the WHO criteria for symptomatic HIV infection(7), as viral confirmatory tests were not possible in the study set up. Seropositive children were further classi-fied as per Center for Disease control (CDC) case definition(8). and seropositive children of less than 18 months, who didn’t fulfill CDC definition were considered as perinatally exposed.
A total of 821 children, i.e., 5.5% of 14990 admissions during study period were screened. Of them, 124 were found sero-positive, with an overall seropositivity rate (SPR) of 0.83% among all screened cases. Western blot test could be done in 23 cases, and was positive in all of them. SPR among hospitalized cases increased from 0.21% in 1992 to 1.49% in 1998, rise being more marked during 1997-98. Number of cases screened also increased gradually and nearly doubled in 1998. Throughout the study period, 9.8% to 19.0% of screened cases were found seropositive (Table 1).
Ninety one per cent children were initially screened on clinical suspicion, of whom 11.9% were seropositive. However, in most of them mothers were found seropositive on retrograde testing. In comparison, half of the 68 cases tested for high risk history were seropositive. Overall, 72.6% serospositive cases in this study were investigated on the clinical grounds alone, before their high risk status was known. While 46.8% of seropositive cases were below 18 months of age, 17.8% children were more than five years old at the time of diagnosis. A distinct male preponderance was noted, more apparent in older children (Table II).
In 103 cases, mothers were either seropositive or had died of AIDS (4 cases). Of these, 21 (20.4%) were known commercial sex workers (CSW). Another 11 cases were also probably perinatally infected, though their mothers could not be tested. Among the six cases of the transfusion related infection (3 nutritional anemia, 2 hemolytic anemia, 1 idiopathic thrombocytopenic purpura), five were diagnosed before 1994. All had received transfusion at peripheral hospitals or nursing homes, five of them getting after 1988, when blood screening became mandatory. Two street boys aged 5 and 7 years had history of probable sexual abuse. In 2 cases, source could not be identified. Eighty two (66.1%) seropositive cases fulfilled CDC criteria(8). Forty-two cases of under 18 months were considered as ‘perinatally exposed’, though all of them fulfilled WHO criteria for symptomatic HIV infection(7).
HIV infected children are usually identified at the entry points of infection, i.e., by screening of babies born to seropositive mothers or recipients of blood transfusions. Review of literature reveals sparsity of surveillance studies for HIV infection in clinically suspected children. Emodi and Okafur from Nigeria reported 23% seropositivity among children with clinically suspected HIV infection, during 1989-96(9). Recently, Merchant and Shroff from Mumbai reported 24% and 18% sero-positivity in children with chronic diarrhea or disseminated tuberculosis, respectively(10). Their findings as well as 15.1% seropositivity seen in present study indicate that pediatric HIV infection is an emerging reality in Mumbai. However, it is to be noted that the study hospital is in a high risk locality and our observations may not be representative. Rising SPR among hospitalized children seen in this study, is perhaps a result of marked rise in seroprevalence among ante-natal mothers. However partly, this rise may also be due to more liberal screening due to increased awareness and easier availability of diagnostic facilities. Higher positivity among screened cases, seen in recent years, further indicates rising prevalence of infection. But it is also possible that as clinicians become familiar with clinical presentation, they may become more selective in ordering screening thereby improving yield of the screening tests. Lower SPR during 1995-96 was probably due to retrospective data collection for this period, when screening criteria might not have been stringent. Though the SPR in cases screened on the clinical grounds alone was much lower than in cases with high risk factors, it is noteworthy that nearly three-fourths of the seropositive cases were taken up for initial screening on clinical suspicion alone. Obviously, clinical suspicion based screening appears an effective strategy for detection of new cases, though may not be as rewarding as high risk approach. In this study, 46.8% cases were less than eighteen months old. Confirmation of infection in this age group is a problem in developing countries, due to non-affordability of confirmatory tests. Application of CDC criteria(8) for clinical diagnosis is also difficult, as it requires sophisticated labo-ratory support. WHO criteria for clinical diagnosis of symptomatic HIV infection(7) appear to be a more practical alternative in these resource poor settings. All younger cases in this study who failed to meet stricter CDC criteria and were categorized as peri-natally exposed, fulfilled WHO case defini-tion. This observation indicates that even these perinatally exposed cases were also most likely infected. Male preponderance in the present study may be due to gender bias in self referral to the hospital. However, the sex ratio became more discriminatory in older age groups, being 1.3 : 1 in less than 18 months old cases as compared to 3.4 : 1 in children above 5 years of age. Whether this difference was merely due to more obvious gender bias in older children or also due to differences in clinical progression of the disease in two sexes is not clear. With stricter transfusion regulations, horizontal spread of HIV in children is becoming exceedingly uncommon. Rarity of transfusion related cases in this study may also be due to the fact that most of the thalassemics in this hospital are treated in the hematology rather than the pediatric depart-ment. In the study hospital, SPR among frequently transfused children is around 5% (personal communication). The fact that cases of transfusion related infection are still seen, despite mandatory screening, indicate either problems of compliance or fallibility of screening tests. As most of these cases have history of transfusions at peripheral health care centers, monitoring of transfusion practices, specially in these set-ups, need to be strengthened. To conclude, the present study indicates rising seroprevalence of pediatric HIV infection in India and suggests screening on clinical suspicion as an additional pick up point for detection of new cases along with high risk screening programs. Contributors : MA conceptualised, co-ordinated and analyzed the study as well as drafted the paper; he will act as guarantor for the paper. GVK, a microbiologist conducted ELISA/rapid tests and contributed in interpretation of data. RG and MC participated in data collection and analysis. SMJ and KRL participated in data interpretation as well as critical review of the contents during drafting of the paper.
Funding:
None.
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
