Жұқпағаннан кейінгі профилактикалық емдер

Preventive medical treatment after exposure

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.

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 is being studied for its potential use as post exposure prophylaxis against COVID 19.

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. Rabies vaccine is given to both humans and animals who have been potentially exposed to rabies.

AZT was approved as a treatment for AIDS in 1987. Healthcare workers would occasionally be exposed to HIV during work. Some people thought to try giving health care workers AZT to prevent seroconversion. This practice dramatically decreased the incidence of seroconversion among health workers when done under certain conditions. Later the questions arose of whether to give HIV treatment after known exposure or high risk of exposure. Early data from preclinical studies established the efficacy of AZT in preventing transmission of HIV infection. AZT was also seen to reduce maternal infant transmission of HIV in a randomized controlled trial, suggesting AZT's post exposure prophylaxis (PEP) use. Subsequent data show combination antiretroviral therapy is significantly superior than AZT in reducing perinatal transmission rates. In addition, AZT is generally no longer recommended due to poor tolerance resulting in high rates of patient noncompliance. Non occupational exposures include cases when a condom breaks while a person with HIV has sex with an HIV negative person in a single incidence, or in the case of unprotected sex with an anonymous partner, or in the case of a non habitual incident of sharing a syringe for injection drug use. Evidence suggests that PEP also reduces the risk of HIV infection in these cases. In 2005, the US DHHS released the first recommendations for non occupational PEP (nPEP) use to lower risk of HIV infection after exposures. The recommendations were replaced with an updated guideline in 2016. Occupational exposures include needlestick injury of health care professionals from an HIV infected source. In 2012, the US DHHS included guidelines on occupational PEP (oPEP) use for individuals with HIV exposures occurring in health care settings. Since taking HIV attacking medications shortly after exposure was proven to reduce the risk of contracting HIV, this led to research into pre exposure prophylaxis by taking medication before a potential exposure to HIV occurred. A report from early 2013 revealed that a female baby born with the HIV virus displayed no sign of the virus two years after high doses of three antiretroviral drugs were administered within 30 hours of her birth. The findings of the case were presented at the 2013 Conference on Retroviruses and Opportunistic Infections in Atlanta, U. S. and the baby is from Mississippi, U. S. The baby—known as the "Mississippi baby"—was considered to be the first child to be "functionally cured" of HIV. However, HIV re emerged in the child as of July 2014.

Initiation of post exposure prophylaxis with the use of antiretroviral drugs is dependent on a number of risk factors, though treatment is usually started after one high risk event. In order to determine whether post exposure prophylaxis is indicated, an evaluation visit will be conducted to consider risk factors associated with developing HIV. Assessments at this visit will include whether the at risk person or the potential source person are HIV positive, details around the potential HIV exposure event, including timing and circumstances, whether other high risk events have occurred in the past, testing for sexually transmitted diseases, testing for hepatitis B and C (nPEP is also effective against hepatitis B), and pregnancy tests for women of childbearing potential. The CDC recommends PEP for any HIV negative person who has recently been exposed to HIV for any reason. After 72 hours PEP is much less effective, and may not be effective at all. While there is compelling data to suggest that PEP after HIV exposure is effective, there have been cases where it has failed. Failure has often been attributed to the delay in receiving treatment (greater than 72 hours post exposure), the level of exposure, and/or the duration of treatment (lack of adherence to the 28 day regimen). In addition, since the time and level of non occupational exposures are self reported, there is no absolute data on the administration timeframe to which PEP would be efficacious. The standard antibody window period begins after the last day of PEP treatment. People who received PEP are typically advised to get an antibody test at 6 months post exposure as well as the standard 3 month test. People initiating nPEP treatment typically receive a 28 day starter pack, as opposed to a 3 7 day starter pack, to facilitate strong medication adherence.

If the person exposed is an HBsAg positive source (a known responder to HBV vaccine) then if exposed to hepatitis B a booster dose should be given. If they are in the process of being vaccinated or are a non responder they need to have hepatitis B immune globulin (HBIG) and the vaccine. For known non responders HBIG and the vaccine should be given whilst those in the process of being vaccinated should have an accelerated course of HBV vaccine.

Persons exposed to hepatitis C should be tested monthly with PCR, and if seroconversion occurs then treatment with interferon, or possibly ribavirin.

A 60 day course of oral ciprofloxacin should be given when exposure to anthrax is suspected.

A single 200 milligram oral dose of doxycycline may be used within 3 days of a deer tick bite in a high risk area (such as New England), if the tick was attached for at least 36 hours.

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.