Brincidofovir, sold under the brand name Tembexa, is an antiviral drug used to treat smallpox. Brincidofovir is a prodrug of cidofovir. Conjugated to a lipid, the compound is designed to release cidofovir intracellularly, allowing for higher intracellular and lower plasma concentrations of cidofovir, effectively increasing its activity against dsDNA viruses, as well as oral bioavailability.The most common side effects include diarrhea, nausea, vomiting, and abdominal pain.Brincidofovir was approved for medical use in the United States in June 2021. Medical uses
Brincidofovir is indicated for the treatment of human smallpox disease caused by variola virus. Mechanism of Action
Brincidofovir is a pro-drug that is composed of cidofovir, conjugated with a lipid molecule. The lipid aspect of the molecule takes on the action of endogenous lysopghosphatidyl choline, which then is able to enter cells in the body which are infected with smallpox. Once the infected cell takes in the drug, the drug cleaves to generate cidofovir. Cidofovir is then consequently phosphorylated to yield Cidofovir Diphosphate, which is the active drug.Cidofovir diphosphate arises from two key mechanisms. Firstly, cidofovir diphosphate inhibits the variola viruss DNA-polymerase mediated DNA synthesis.The second mechanism is that the drug acts as an acyclic nucleotide and incorporates itself into the viral DNA chain, which then stops viral DNA synthesis. Pharmacokinetics
The oral bioavailability of Brincidofovir is 13.4% as a tablet and 16.8% in a suspension.
With proper testing and diagnosis, the mortality rate falls to less than 1%. Antibiotics such as azithromycin are particularly effective in treating the disease. Epidemiology
Factors outside the household, such as unclean food from street vendors and flooding, help distribute the disease from person to person. Because of poverty and poor hygiene and insanitary conditions, the disease is more common in less-industrialized countries, principally owing to the problem of unsafe drinking water, inadequate sewage disposal, and flooding. Occasionally causing epidemics, paratyphoid fever is found in large parts of Asia, Africa, and Central and South America. Many of those infected get the disease in Asian countries. About 16 million cases occur a year, which result in about 25,000 deaths worldwide. References
Further reading

"Typhoid and Paratyphoid Fever." Communicable Disease Management Protocol. November 2001 https://www.gov.mb.ca/health/publichealth/cdc/protocol/typhoid.pdf. "Typhoid and Paratyphoid Fever." Public Health Notifiable Disease Management Guidelines. Disease Control and Prevention. Alberta Health and Wellness: June 2013 https://web.archive.org/web/20130925214850/http://www.health.alberta.ca/documents/Guidelines-Paratyphoid-Fever-2013.pdf