***TASK***
the task is to simplify the input abstract of a biomedical literature

***INPUT***
the input is the abstract of a biomedical literature

***OUTPUT***
the output is the simplified abstract for the input abstract of a biomedical literature

***DOCUMENTATION***

***EXAMPLES***

Input: Three cohort studies were included in the review. They examined 484 patients with HIV infection who received YF immunisation. Patients with HIV infection developed significantly lower concentrations of neutralising antibodies in the first year post immunisation compared to uninfected patients, though decay patterns were similar for recipients regardless of HIV infection. No study patient with HIV infection suffered serious adverse events as a result of YF vaccination. YF vaccination can produce protective levels of neutralising antibodies in HIV patients. Immunogenicity of YF vaccine is slightly less in HIV-infected patients compared to HIV-uninfected patients. No serious adverse events related to YF vaccine were observed in HIV-infected study participants. At time of immunisation, higher CD4 cell counts and lower HIV RNA levels in patients with HIV infection seem to be key determinants for development of protective titres of neutralising antibodies. The quality of the evidence for all outcomes was low to very low. YF vaccine may potentially be used safely in HIV-infected patients, although our conclusions are limited by small numbers of patients who have been reported. To assure maximum effectiveness YF vaccine should be given to HIV-infected patients after HIV replication has been suppressed.
Output:

The purpose of this review was to assess the risks and benefits of YF vaccine for people living with HIV. We found three cohort studies that addressed this question. One study in children, from a time before effective widespread use of antiretroviral drugs, found that YF vaccine worked much less well in children with HIV than it did in those without HIV. Two studies in adults found that the immune response to yellow fever vaccine was slightly lower in HIV-infected patients. No severe adverse events were observed in patients in these studies. However, because the numbers of people with HIV who have received YF vaccine is small, and serious side effects are uncommon in people without HIV infection, we are not positive about its safety. When it does need to be used, it should be given to people whose viral loads are low and CD4 counts are high.