Post-exposure prophylaxis
preventive medical treatment started after exposure to a pathogen to prevent infection occurring
Post-exposure prophylaxis, also known as post-exposure prevention (PEP), is any preventive medical treatment started after exposure to a pathogen in order to prevent the infection from occurring.
It should be contrasted with pre-exposure prophylaxis, which is used before the patient has been exposed to the infective agent.
COVID-19
In 2021, the US FDA gave emergency use authorization (EUA) to bamlanivimab/etesevimab for post-exposure prophylaxis against COVID-19. However, due to its reduced effectiveness against Omicron variants of the SARS-CoV-2 virus, it is no longer recommended for this purpose.
Ensitrelvir has been studied for its potential use as post-exposure prophylaxis against COVID-19 in a phase 3 clinical trial. In 2025, the SCORPIO-PEP trial found the treatment with ensitrelvir significantly reduced the incidence of symptomatic COVID-19 in people who had a household exposure to the illness compared to a placebo. In clinical observations, only 2.9% of the ensitrelvir group developed symptoms, versus 9.0% in the control group, representing a 67% reduction in risk. In September 2025, the FDA accepted a New Drug Application from the manufacturer for ensitrelvir as PEP for COVID-19, and was approved for this use on 29 May 2026.
Rabies
PEP is commonly and very effectively used to prevent the onset of rabies after a bite by a suspected-rabid animal, since diagnostic tools are not available to detect rabies infection prior to the onset of the nearly always-fatal disease. The treatment consists of a series of injections of rabies vaccine and immunoglobulin.
The public source identifies “Post-exposure prophylaxis” as preventive medical treatment started after exposure to a pathogen to prevent infection occurring. This brief keeps that definition visible, then builds a research path around Post-exposure, prophylaxis and preventive.
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Named sources, stable identifiers and responsible institutions provide the strongest route from overview to verifiable evidence. The source revision retrieved here is dated Sep 1, 2026. The linked authority identifier is Q1361206. None of the 0 selected statements returned an explicit reference. The first chronological checks are 2021, 2025 and 2026.
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This entry incorporates text from “Post-exposure prophylaxis” on English Wikipedia. Contributors are listed in the page history. Text is available under the Creative Commons Attribution-ShareAlike 4.0 License. Selected authority identifiers and statements are retrieved from Wikidata under CC0; their references and qualifiers remain part of the verification path.