Search

Background: Travellers frequently visit popular destinations like Brazil, India, Peru, Thailand, and Tanzania, each presenting varying malaria risks. The extent to which travellers enter high-risk malaria-endemic areas in destinations with heterogeneous malaria risk remains unclear. We used geo-location via smartphone application to (i) describe where travellers go within countries with heterogeneous malaria risk (Brazil, India, Peru, Thailand), and (ii) compare mosquito bite prevention behaviours between these destinations and Tanzania, considered entirely high-risk for malaria., Methods: This analysis is a sub-study of the TOURIST2 cohort, which prospectively recruited 1000 travellers (≥ 18 years, travelling ≤ 4 weeks) from Swiss travel clinics (Zurich and Basel) between 09/2017-04/2019. We included 734 travellers to Brazil, India, Peru, Thailand, and Tanzania who provided geo-location data. Daily health and geo-location data were collected using a smartphone application. Malaria risk was categorised using 2022 malaria maps from the Swiss Expert Committee for Travel Medicine., Results: Of the 734 travellers, 525 travelled to Brazil, India, Peru, and Thailand, and 225 to Tanzania. In Brazil, India, Peru, and Thailand, only 2% (n = 13) visited high-risk malaria areas. In Peru, 4% (n = 4) visited a high-risk area; in Brazil, 3% (n = 6); in Thailand, 2% when crossing the border into Myanmar (n = 3); and in India, 0%. Travellers to high-risk areas were more often male (62%), slightly older (median age 42.0), and planned longer trips (median 23.0 days) than other travellers. No participants were diagnosed with malaria. Travellers to Brazil, India, Peru and Thailand used mosquito bite prevention measures less frequently than travellers to Tanzania. Those in Tanzania had higher, but still suboptimal, use of insect spray (65% of travel-days)., Conclusions: Travellers to Brazil, India, Peru, and Thailand rarely visited high-risk malaria areas, and their adherence to mosquito bite prevention measures was generally low. In Tanzania, adherence was higher but still suboptimal., (© The Author(s) 2024. Published by Oxford University Press on behalf of International Society of Travel Medicine.)

Background: In human immunodeficiency virus (HIV)-infected individuals, the immune response over time to yellow fever vaccination (YFV) and the necessity for booster vaccination are not well understood., Methods: We studied 247 participants of the Swiss HIV Cohort Study (SHCS) with a first YFV after HIV diagnosis and determined their immune responses at 1 year, 5 years, and 10 years postvaccination by yellow fever plaque reduction neutralization titers (PRNTs) in stored blood samples. A PRNT of 1:≥10 was regarded as reactive and protective. Predictors of vaccination response were analyzed with Poisson regression., Results: At vaccination, 82% of the vaccinees were taking combination antiretroviral therapy (cART), 83% had suppressed HIV RNA levels (<400 copies/mL), and their median CD4 T-cell count was 536 cells/μL. PRNT was reactive in 46% (95% confidence interval [CI], 38%-53%) before, 95% (95% CI, 91%-98%) within 1 year, 86% (95% CI, 79%-92%) at 5 years, and 75% (95% CI, 62%-85%) at 10 years postvaccination. In those with suppressed plasma HIV RNA at YFV, the proportion with reactive PRNTs remained high: 99% (95% CI, 95%-99.8%) within 1 year, 99% (95% CI, 92%-100%) at 5 years, and 100% (95% CI, 86%-100%) at 10 years., Conclusions: HIV-infected patients' long-term immune response up to 10 years to YFV is primarily dependent on the control of HIV replication at the time of vaccination. For those on successful cART, immune response up to 10 years is comparable to that of non-HIV-infected adults. We recommend a single YFV booster after 10 years for patients vaccinated on successful cART, whereas those vaccinated with uncontrolled HIV RNA may need an early booster.

The immune response to yellow fever (YF) vaccine and its safety among HIV-infected individuals living in YF endemic areas is not well understood. Following a national YF preventive immunisation campaign in Mali in April 2008, we assessed the immunogenicity and safety of 17D yellow fever vaccine (17DV) among HIV-infected patients in two HIV treatment centres in Bamako, Mali, by testing for neutralising antibodies and identifying serious adverse events following immunisation (AEFI). A YF neutralisation titre (NT) of 1:≥20 was considered to be adequate and protective. A serious AEFI included hospitalisation, any life-threatening condition, or death, occurring within 30 days following 17DV administration. Of 115 HIV-infected patients who reported having received 17DV, 110 (96%) were on combination antiretroviral therapy and 83 patients were tested for neutralising antibodies. Around the time of vaccination, median CD4 cell count was 389 cells/mm(3) (IQR 227-511cells/mm(3)); HIV-RNA was undetectable in 24 of 46 patients tested. Seventy-six (92%) of 83 participants had adequate immune titres 9 months after the immunisation campaign. Previous vaccination or flavivirus exposure could contribute to this finding. No serious AEFI was found in the 115 participants. In this small series, YF vaccine appeared to be immunogenic with a favourable safety profile in HIV-infected patients on antiretroviral therapy. Higher CD4 cell counts and suppressed HIV-RNA were associated with the presence of an adequate immune titre and higher NTs., (Copyright © 2012 Royal Society of Tropical Medicine and Hygiene. Published by Elsevier Ltd. All rights reserved.)

Background: Yellow fever vaccine (17DV) has been investigated incompletely in human immunodeficiency virus (HIV)-infected patients, and adequate immunogenicity and safety are of concern in this population., Methods: In the Swiss HIV Cohort Study, we identified 102 patients who received 17DV while they were HIV infected. We analyzed neutralization titers (NTs) after 17DV administration using the plaque reduction neutralization test. NTs of 1:>or=10 were defined as reactive, and those of 1:<10 were defined as nonreactive, which was considered to be nonprotective. The results were compared with data for HIV-uninfected individuals. Serious adverse events were defined as hospitalization or death within 6 weeks after receipt of 17DV., Results: At the time of 17DV administration, the median CD4 cell count was 537 cells/mm(3) (range, 11-1730 cells/mm(3)), and the HIV RNA level was undetectable in 41 of 102 HIV-infected patients. During the first year after vaccination, fewer HIV-infected patients (65 [83%] of 78; P = .01) than HIV-uninfected patients revealed reactive NTs, and their NTs were significantly lower (P < .001) than in HIV-uninfected individuals. Eleven patients with initially reactive NTs lost these reactive NTs

Loiasis, caused by the filarial parasite Loa loa, is endemic in West and Central Africa. Ivermectin has been shown to be an effective treatment of loiasis. We report the case of a 20-year-old woman originally from Cameroon who was infected by the L. loa parasite and developed severe hepatitis, identified 1 month after a single dose of ivermectin. Liver biopsy showed intralobular inflammatory infiltrates, confluent necrosis and apoptosis, compatible with drug-induced liver disease. To our knowledge, this is the first case of ivermectin-induced severe liver disease published in the literature.