SummaryBackgroundBCG vaccination provides incomplete protection against tuberculosis in infants. A new vaccine, modified Vaccinia Ankara virus expressing antigen 85A (MVA85A), was designed to enhance the protective efficacy of BCG. We aimed to assess safety, immunogenicity, and efficacy of MVA85A against tuberculosis and Mycobacterium tuberculosis infection in infants.MethodsIn our double-blind, randomised, placebo-controlled phase 2b trial, we enrolled healthy infants (aged 4–6 months) without HIV infection who had previously received BCG vaccination. We randomly allocated infants (1:1), according to an independently generated sequence with block sizes of four, to receive one intradermal dose of MVA85A or an equal volume of Candida skin test antigen as placebo at a clinical facility in a rural region near Cape Town, South Africa. We actively followed up infants every 3 months for up to 37 months. The primary study outcome was safety (incidence of adverse and serious adverse events) in all vaccinated participants, but we also assessed efficacy in a protocol-defined group of participants who received at least one dose of allocated vaccine. The primary efficacy endpoint was incident tuberculosis incorporating microbiological, radiological, and clinical criteria, and the secondary efficacy endpoint was M tuberculosis infection according to QuantiFERON TB Gold In-tube conversion (Cellestis, Australia). This trial was registered with the South African National Clinical Trials Register (DOH-27-0109-2654) and with ClinicalTrials.gov on July 31, 2009, number NCT00953927FindingsBetween July 15, 2009, and May 4, 2011, we enrolled 2797 infants (1399 allocated MVA85A and 1398 allocated placebo). Median follow-up in the per-protocol population was 24·6 months (IQR 19·2–28·1), and did not differ between groups. More infants who received MVA85A than controls had at least one local adverse event (1251 [89%] of 1399 MVA85A recipients and 628 [45%] of 1396 controls who received the allocated intervention) but the numbers of infants with systemic adverse events (1120 [80%] and 1059 [76%]) or serious adverse events (257 [18%] and 258 (18%) did not differ between groups. None of the 648 serious adverse events in these 515 infants was related to MVA85A. 32 (2%) of 1399 MVA85A recipients met the primary efficacy endpoint (tuberculosis incidence of 1·15 per 100 person-years [95% CI 0·79 to 1·62]; with conversion in 178 [13%] of 1398 infants [95% CI 11·0 to 14·6]) as did 39 (3%) of 1395 controls (1·39 per 100 person-years [1·00 to 1·91]; with conversion in 171 [12%] of 1394 infants [10·6 to 14·1]). Efficacy against tuberculosis was 17·3% (95% CI −31·9 to 48·2) and against M tuberculosis infection was −3·8% (–28·1 to 15·9).InterpretationMVA85A was well tolerated and induced modest cell-mediated immune responses. Reasons for the absence of MVA85A efficacy against tuberculosis or M tuberculosis infection in infants need exploration.FundingAeras, Wellcome Trust, and Oxford-Emergent Tuberculosis Consortium (OETC).

Vaccines to protect against tuberculosis (TB) are urgently needed. We performed a case–control analysis to identify immune correlates of TB disease risk in Bacille Calmette–Guerin (BCG) immunized infants from the MVA85A efficacy trial. Among 53 TB case infants and 205 matched controls, the frequency of activated HLA-DR+ CD4+ T cells associates with increased TB disease risk (OR=1.828, 95% CI=1.25–2.68, P=0.002, FDR=0.04, conditional logistic regression). In an independent study of Mycobacterium tuberculosis-infected adolescents, activated HLA-DR+ CD4+ T cells also associate with increased TB disease risk (OR=1.387, 95% CI=1.068–1.801, P=0.014, conditional logistic regression). In infants, BCG-specific T cells secreting IFN-γ associate with reduced risk of TB (OR=0.502, 95% CI=0.29–0.86, P=0.013, FDR=0.14). The causes and impact of T-cell activation on disease risk should be considered when designing and testing TB vaccine candidates for these populations.

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Background: The value of quantitative interferon-γ release assay results for predicting progression from Mycobacterium tuberculosis infection to active disease is unknown. Methods: We analysed data from a reported vaccine efficacy trial of MVA85A in South Africa. QuantiFERON-TB Gold In-Tube (QFT) negative, HIV uninfected infants aged 18–24 weeks were enrolled. We stratified participants by quantitative QFT result (IFN-γ <0.35, 0·35–4·00, >4·00 IU/ml) at the intermediate study visit (Day 336) and determined risk of progression to active tuberculosis disease over the subsequent 6–24 months. No QFT differences were observed between placebo and MVA85A groups; therefore, both groups were included in analyses. Study clinicians were not blinded to QFT values, but strict case definitions were used and excluded QFT results. Findings: Among 2,512 infants with QFT tests performed at Day 336, 172 (6·8%) were positive. Compared with QFT non-converters (disease incidence 0·7 per 100 person-years; 95% CI: 0·4–1·1), children with QFT conversion at IFN-γ values between 0·35–4·00 IU/ml did not have significantly increased risk of disease (2·5 per 100 person-years; 95% CI: 0·4–9·4; IRR 3·7; p=0·23). However, QFT conversion at IFN-γ values >4·00 IU/ml was associated with markedly increased disease incidence (28·0 per 100 person-years; 95% CI: 14·9–45·7) compared to nonconverters (IRR 42·5; p<0·0001); and compared to children with IFN-γ values between 0·35–4·00 IU/ml (IRR: 11·4; p=0·00047). Among 91 QFT converters with a repeat test, 53 (58·2%) reverted from positive to negative. QFT reversion risk was inversely associated with IFN-γ value at QFT conversion and was highest (47/61; 77·0%) with IFN-γ values <4·00 IU/ml. Interpretation: In young children, tuberculosis disease risk was not significantly elevated, and QFT reversion was common, following QFT conversion at IFN-γ values up to 10 times the recommended test threshold. By contrast, QFT conversion at very high IFN-γ values (>4·00 IU/ml) warrants intensified diagnostic and preventive intervention for extremely high risk of tuberculosis disease.

To study antibiotic efficacy, 29 patients with leptospirosis were treated in a randomized, double-blinded fashion with doxycycline, 100 mg orally twice a day, or placebo. Therapy was given for 7 days in a hospital, and patients were followed for 3 weeks afterwards. Duration of illness before therapy and severity of illness were the same in both groups. Doxycycline reduced the duration of illness by 2 days and favorably affected fever, malaise, headache, and myalgias. Treatment prevented leptospiruria and had no adverse effects. Doxycycline is effective in therapy for patients with leptospirosis.