virus may be controlled by quarantining (at least for 6 weeks from the date of last exposure) the infected animals and tracing their contacts. Adherence to specific instructions from the local and global public health authorities is mandatory. Increasing awareness and action (adequate decisions, medical staff, sampling, surveillance, education) both by local and international authorities are of central importance. At hospitals in developed countries, when suspecting a case of monkeypox (eg, a patient with fever, skin lesions, and history of visiting endemic area or contact with patients), the patient should immediately be placed in a negative air pressure isolation room, or a private room if such facilities are unavailable. Standard, contact, and droplet precautions should all be taken. Infection control personnel should be contacted without delay. In developed countries, likewise, increasing awareness among health care personnel about the disease and its endemic areas is an important precaution. VACCINES AGAINST MONKEYPOX Although new vaccines are being developed for monkeypox, there is a need for conducting controlled clinical trials to evaluate the impact of the use of smallpox vaccines for prevention of monkeypox or modifying disease severity. Studies should focus on the cost/benefit of population-level vaccination and investigation of alternative vaccination strategies such as targeting vaccination to affected areas, contacts, and health care workers, and wider geographic areas. Currently the CDC recommends preexposure smallpox vaccination for field investigators, veterinarians, animal control personnel, contacts of monkeypox patients, researchers, and health care workers caring for such patients and their contacts.3 Can the Smallpox Vaccine Available Be Used to Protect Against Monkeypox? Percutaneous inoculation with vaccinia virus elicits a broad and heterogeneous serum antibody response targeting a large number of antigenic determinants of vaccinia virus.73,74 The viral inhibitory activity of serum from immune subjects with crossHuman Monkeypox 11 neutralizing activity to vaccinia virus, MPXV, and VARV is presumably composed of antibodies with diverse specificities.75–77 Production of first-generation live attenuated vaccine has been reviewed by the WHO in 1988.9 A considerable proportion of the population may have contraindications for the vaccine candidates: 15.2% to 15.8% of the United States population has been estimated to have potential contraindications for taking the live attenuated smallpox vaccine.78 The rates of side effects associated with the live attenuated vaccinia virus in the United States in 1968 were 74 complications and 1 death per 1 million primary vaccinations. Morbidity and mortality rates were highest for infants, with 112 complications and 5 deaths per million primary vaccinations.79 In 2002, the US Department of Defense resumed a program for widespread smallpox vaccinations because of a perceived threat of biological warfare. A total of 540,824 military personnel were vaccinated with a New York City Board of Health (NYCBH) strain of vaccinia, “DryVax,” from December 2002 through December 2003. Dryvax was produced by infecting the skin of calves using the NYCBH strain as seed virus. Of these, 67 (1 in 8000) developed myopericarditis.80,81 The highest rate of postvaccine encephalitis (pvE) was found with the Bern strain (44.9 expected cases per million vaccines), followed by the Copenhagen strain (33.3 per million vaccines), the Lister strain (26.2 per million vaccines), and the NYCBH strain with the lowest rate (2.9 per million vaccinations).82 ADDRESSING GAPS IN KNOWLEDGE AND STRENGTHENING PUBLIC HEALTH PREPAREDNESS Most data available on monkeypox are obtained from individual case or outbreak reports, and from passive intermittent surveillance, none of which convey an accurate overall picture. The current major gaps in monkeypox knowledge, the changing epidemiologic and clinical presentations, and the multifarious factors involved in monkeypox transmission argue the need to strengthen outbreak preparedness efforts. There remains an urgent need for developing public health and surveillance capacities in Central and West Africa to guide appropriate surveillance, data collection, prevention, preparedness, and response activities to monkeypox and other emerging and reemerging infections with epidemic potential. Advancing public health preparedness and aligning proactive surveillance activities to priority research will require coordinated, locally led, multidisciplinary efforts adjusted closely to capacity development and training. SUMMARY The spread of monkeypox across West Africa over the past decade and the ongoing outbreak in Nigeria indicates that it is no longer “a rare viral zoonotic disease that occurs primarily in remote parts of Central and West Africa, near tropical rainforests.” Its potential for further spread both regionally and internationally remains a major concern.28,29 The ecologic, zoonotic, epidemiologic, clinical, and public health aspects of monkeypox remain inadequately characterized.33,36,44,45 The firstgeneration live attenuated vaccinia virus vaccines stored for emergency purposes in many countries cannot be used because of severe adverse reactions. Discontinuing the smallpox vaccination