If the live vaccines are administered non-simultaneously and within 4 weeks, it is recommended that the second vaccine administered should be repeated. We report the successful vaccination and generation of a protective immune response to yellow fever (YF) vaccine that was administered to an adult traveler 21 days after receiving another live viral vaccine. A 60-year-old female was seen at the Adult Immunization and Travel Clinic of the San Francisco Department of Public Health 6 days prior to departing on a 2-week visit to western Uganda. She was born and resided in the United States, was in good health, and had no Pirfenidone molecular weight history of

prior flavivirus infection, receipt of YF or Japanese encephalitis vaccinations, or travel to a YF endemic area. The CDC recommends that all travelers ≥9 months of age visiting Uganda be vaccinated against YF.2 Furthermore, at the time of consultation there was even greater concern about the risk of natural infection because of an outbreak of YF occurring in the northern part of the country.3 The client reported receiving an injection of zoster vaccine (Zostavax, Merck Sharp & Dohme, Whitehouse Station, NJ, USA), a live-attenuated viral vaccine, at a pharmacy 21 days earlier. We informed

her that the live zoster vaccine could affect her response to YF vaccine, and that she could be at increased risk of an adverse reaction to YF vaccine due to her age.4 Despite these considerations, and in light of the ongoing outbreak, she agreed with our recommendation in favor of vaccination against YF. We administered YF vaccine (YF-Vax; Sanofi this website Pasteur, Swiftwater,

PA, USA) as well as inactivated vaccines against typhoid, meningococcal infection, and polio (Typhim Vi, Menactra, and IPOL; Sanofi Pasteur). We also prescribed a regimen of daily malaria chemoprophylaxis with atovaquone–proguanil, and instructed her to use prevention measures to reduce her mosquito exposure. She returned to our clinic 5 weeks later, in preparation for a 6-month trip to the same region in Uganda. According to published CDC recommendations, she should have been given a second dose of YF vaccine. However, because her age Rucaparib clinical trial was a precaution to initial vaccination, and since there was sufficient time to do so, we opted to check her immunity to YF before administering a second dose of the vaccine. A serum specimen was obtained and analyzed at the CDC Division of Vector-Borne Diseases in Fort Collins, Colorado, for neutralizing antibodies against YF virus. At CDC, a 90% endpoint plaque reduction neutralization test (PRNT90) titer of ≥20 is considered protective against YF virus infection.4 Our client had a titer of 1,280 in her serum obtained 35 days after vaccination. Infection with YF virus, a mosquito-borne flavivirus, most commonly is asymptomatic or causes mild febrile illness.