Predicting the long-term impact of rotavirus vaccination in 112 countries from 2006 to 2034: A transmission modeling analysis

Rotavirus vaccination has been shown to reduce rotavirus burden in many countries, but the long-term magnitude of vaccine impacts is unclear, particularly in low-income countries. We use a transmission model to estimate the long-term impact of rotavirus vaccination on deaths and disability adjusted life years (DALYs) from 2006 to 2034 for 112 low- and middle-income countries. We also explore the predicted effectiveness of a one- vs two- dose series and the relative contribution of direct vs indirect effects to overall impacts. To validate the model, we compare predicted percent reductions in severe rotavirus cases with the percent reduction in rotavirus positivity among gastroenteritis hospital admissions for 10 countries with pre- and post-vaccine introduction data. We estimate that vaccination would reduce deaths from rotavirus by 49.1 % (95 % UI: 46.6-54.3 %) by 2034 under realistic coverage scenarios, compared to a scenario without vaccination. Most of this benefit is due to direct benefit to vaccinated individuals (explaining 69-97 % of the overall impact), but indirect protection also appears to enhance impacts. We find that a one-dose schedule would only be about 57 % as effective as a two-dose schedule 12 years after vaccine introduction. Our model closely reproduced observed reductions in rotavirus positivity in the first few years after vaccine introduction in select countries. Rotavirus vaccination is likely to have a substantial impact on rotavirus gastroenteritis and its mortality burden. To sustain this benefit, the complete series of doses is needed.

[Primary results of antiretroviral treatment among HIV/AIDS infected children in Lomé (Togo)]

Since 2004 in Togo HIV/AIDS infected children have, free of charge, access to antiretroviral drugs according to the national program. The aim of this study was to investigate the clinical, biological and prognosis aspects of anti-retroviral treatment on HIV/AIDS infected children.

PATIENTS AND METHOD

We conducted a cross sectional study on 72 HIV/AIDS infected children with anti-retroviral treatment, under the supervision of clinicians within 3 associations specialized in the management of subjects infected by HIV/SIDA at Lomé (Togo).

RESULTS

The average age of children was 6 years 9 months. The middle age to HIV screening was 4 years 2 months. The sex ratio was 1.05. The majority of these children (79.2%) were orphans of at least 1 of their parents. All the children were stemmed from families with modest income. The transmission mother to child was the way of HIV contamination found among all the children. To a certain extent, all the children were infected by the HIV 1. Most of the children (66.7%) receiving an antiretroviral treatment for at least 6 months were asymptomatic and had no more immunodeficiency. After 15 months, the children have gained 464 CD4/mm(3). The initial protocols antiretroviral prescribed among children were: zidovudine-lamivudine-abacavir (36.1%), lamivudine-didanosine-nevirapine (30.5%), lamivudine-stavudine-nevirapine (29.2%), zidovudine-lamivudine-didanosine (4.2%). The digestive disorders have been the first side effects (83.4%). The rate of good observance was middle (51%) and lowered with the increased age of children, and the period of the anti-retroviral treatment.

CONCLUSIONS

Antiretroviral treatment among HIV/AIDS infected children is giving good results in Togo. But many efforts remain to increase the number of beneficiaries.

[Pediatric AIDS at the University Hospital Center-Tokoin (Lomé): the role of protein-calorie malnutrition and a formulation trial of a clinical diagnostic score]

Two cross-sectional studies were carried out in the pediatric ward of the Tokoin Teaching Hospital, Lome. One study determined the prevalence of HIV infection in the 49 malnourished patients treated in the ward in February to March and between August and December 1994. The other was carried out between July 1994 and January 1995 and included 57 other hospitalized children fulfilling at least one of the WHO's pediatric AIDS criteria. The aim was to draw up a screening system for pediatric AIDS based on clinical scores that would be more sensitive than and as specific as the WHO criteria. We tested these criteria and the other signs used in the suggested scoring system using the reference test, HIVchek. The seroprevalence of HIV was 28.6% in malnourished children and transmission was probably exclusively from mother to child. It was difficult to distinguish pediatric AIDS from protein energy malnutrition on clinical grounds, although some of the associated morbidities, including anemia, adenopathy and splenomegaly, were highly suggestive of pediatric AIDS. The second study showed that: 1) the sensitivity of the WHO criteria was low; 2) the best positive predictive values were obtained in cases of polyadenopathy and confirmed HIV infection of the mother. Both these criteria were relatively infrequent; 3) there were 6 criteria significantly associated with HIV infection, each being given a point score according to its Yule coefficient: chronic cough (4 points), chronic diarrhea (3 points), chronic fever (2 points), oropharyngeal candidiasis (2 points) and marasmus (1 point). A score of 4 points was the threshold for suspicion of pediatric AIDS. Our scoring system was more sensitive than the WHO criteria and had similar specificity and positive predictive value. We stress the importance of preventive measures against HIV infection, particularly for women of child-bearing age and suggest a new score test and appropriate clinical definitions for infants and older children.