Energy drinks have increased in popularity in adolescents and young adults; however, concerns have been raised regarding the ingredients in energy drinks and their potential negative effects on health. Caffeine, the most physiologically active ingredient in energy drinks, is generally considered safe by the US Food and Drug Administration (FDA), although adverse effects can occur at varying amounts. Guarana, which contains caffeine in addition to small amounts of theobromine, theophylline, and tannins, is also recognized as safe by the FDA, although it may lead to caffeine toxicity when combined with caffeine. The amount of ginseng in energy drinks is typically far below the amount used as a dietary supplement, and is generally considered safe. Taurine, an intracellular amino acid, has been reported to have positive inotropic effects; however, this claim is not supported by research. Most energy drinks also contain sugar in an amount that exceeds the maximum recommended daily amount. Young athletes are increasingly using energy drinks because of the ergogenic effects of caffeine and the other ingredients found in these beverages. Energy drinks combined with alcohol are also gaining popularity in young adults, which poses significant concerns about health risks. Other health concerns related to consumption of energy drinks include case reports of seizures and cardiac arrest following energy drink consumption and dental enamel erosion resulting from the acidity of energy drinks.

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The USPHS/IDSA guidelines for Prevention of Opportunistic Infections in Persons with human immunodeficiency virus (HIV) recommends that all susceptible HIV+ patients at increased risk for hepatitis A virus (HAV) or with chronic liver disease, be vaccinated against HAV. Immune response to HAV vaccine has not been well studied in HIV+ patients. In particular, there is little information in the literature regarding the effect and relationship of the CD4 count and the immune response in HIV patients. A retrospective analysis of HIV+ patients who received HAV vaccine was performed, and the antibody response to HAV (anti-HAV) measured. Univariate and multivariate analyses were performed to determine predictors of response to vaccine administration. Of the 503 patients evaluated, 138 patients completed their HAV vaccination series and 48% of them had postvaccine anti-HAV positive results (responders). There was no difference in age, race, antiretroviral therapy use, or hepatitis C virus exposure between responders and nonresponders. In univariate analysis, responders were more likely to be female (40.3%vs 21.1%, P = 0.01), have a higher CD4 count at vaccine (508.6 cells/mm3 vs 344.3 cells/mm3, P = 0.001) and marginally lower viral load at vaccine (2.65 log copies vs 2.94 log copies, P = 0.07). Multivariate analysis showed that female gender and higher CD4 count at vaccine were independent predictors of response to vaccine. Forty-eight per cent of our HIV+ patients responded to HAV vaccine administration. This is much lower than reported rates of 100% in HIV-negative patients. Female gender and CD4 count at vaccine, but not CD4 nadir, predicted response to vaccine.