News about Monkeypox, including information about monkeypox vaccines, symptoms, transmission and cases. Monkeypox, which belongs to a family of viruses that includes smallpox, is contagious and can cause skin rash, fever, headache, muscle aches, back pain, low energy and swollen lymph nodes. Most people recover from monkeypox within weeks, but the World Health Organization says the disease is fatal for up to one in 10 people.