bite in a high risk area (such as New England), if the tick was attached for at least 36 hours. Monkeypox and Smallpox The smallpox vaccine decreases the incidence of infection with monkeypox and smallpox and the risk of severe illness even when administered after exposure. The CDC advises "that smallpox vaccine be given within 4 days from the date of exposure to prevent onset of the disease but should be offered up to 14 days post-exposure"; the NHS concurs with this but also urges to vaccinate as soon as possible after exposure. See also Pre-exposure prophylaxis (PrEP) References Further reading External links CDC on nonoccupational HIV postexposure prophylaxis, an article which summarizes more than 100 related research projects HIV/AIDS Post-exposure prophylaxis: WHO Occupational Postexposure Prophylaxis : HRSA HIV/AIDS Bureau, The AIDS Education and Training Centers (AETC) Medical treatments HIV/AIDS Prevention of HIV/AIDS