Research shows that<unk>  (PrEP) is generally safe and well tolerated for most individuals, although some side effects have been noted to occur. Some people experience a "start-up syndrome" involving nausea, headache, and/or stomach issues, which generally resolve within a few weeks of starting the PrEP medication. Research has shown that the use of Truvada as PrEP has been associated with mild to moderate declines in kidney function, mostly associated with older people over 50, those with predisposing conditions such as diabetes, or glomerular filtration rate lower than 90. These declines were usually of no concern, stabilized after several weeks of being on the drug, and reversed once the drug was discontinued. However, these side effects were serious enough for several people on PrEP to file lawsuits against the makers of Truvada as well as the makers of other similar drugs. Osteopenia or bone loss has been reported in clinical studies. Bone loss was not seen as a major concern for ending the service since bone loss was considered minimal and did not lead to osteoporosis. When comparing bone fractures between active participants and control there was no major difference in bone fractures. Fat redistribution and accumulation was more commonly seen in individuals receiving antiretroviral therapy, particularly older antiretrovirals, for the treatment of HIV. No significant changes in fat redistribution or change in fat had been noted when used as a<unk> . Research and study outcome analysis suggests that emtricitabine/tenofovir does not have a significant effect on fat redistribution or accumulation when used as<unk>  in HIV negative individuals. As of early 2018 these studies have not assessed in detail subtle changes in fat distribution that may be possible with the drug when used as PrEP, and statistically significant – though transient – weight changes have been attributed to detectable drug concentrations in the body. Other potential serious side effects of Truvada include acute exacerbations of hepatitis B in individuals with HBV infection, lactic acidosis, and severe hepatomegaly with steatosis. Descovy research and data from public use has shown similar "start-up" effects; however, some data indicates that Descovy is better for one's kidneys and for those with a diagnosis of osteoporosis. The DISCOVER trial that compared descovy versus truvada for PrEP showed that descovy produced safer kidney and bone outcomes. Boxed warnings Both Truvada and Descovy carry a black box warning for the combination of emtricitabine/tenofovir, as this combination of drugs can result in the acute worsening of hepatitis B infection when discontinued. This combination of drugs is also known to increase HIV resistance to these medications when used as<unk>  (PrEP) in individuals who have already (recently) been infected with HIV. It is recommended that individuals continue to periodically get tested to determine their HIV status to ensure proper continuing use of these medications for PrEP.
Pre-exposure prophylaxis
Post-exposure prophylaxis
Transmission-based precautions
Protective isolation
Vaccine storage
Vaccine therapy
Pulse vaccination strategy
Vaccine bundling