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How does PrEP work scientifically in the body to prevent HIV?

PrEP (pre-exposure prophylaxis) is an HIV prevention medicine that is effective at reducing the risk of getting HIV. It is a special medicine used by people who are at high risk of HIV infection, including those who engage in risky sex or injection drug use. PrEP is available as a combination pill that contains tenofovir and emtricitabine, and it’s a proven method to help protect against HIV when taken daily. But, how does PrEP work?

If you’ve been wondering how PrEP works scientifically, continue reading to learn more.  

How HIV attacks
the body

In order to understand how PrEP works, we have to take a look at how HIV attacks the body’s cells. 

The human immunodeficiency virus (HIV) attacks the body’s immune cells, specifically certain T cells. Also known as CD4 helper cells, these T cells are vital for the proper functioning of the immune system. They help coordinate the immune system’s response against pathogens like viruses by recognizing proteins, called antigens, on the surface of pathogens. The T cells then activate certain substances called cytokines to promote the production of antibody-producing cells. Antibodies latch on to pathogens and destroy them. 

When you’re exposed to HIV, the virus lands on T cells and injects its genetic material into the cells. The virus then uses an enzyme called reverse transcriptase to convert its genetic material called RNA into DNA. The viral DNA holds the instructions to create building blocks for new viruses. Essentially, the virus hijacks the T cell and uses it as a factory to create copies of itself. The end result? Death of the T cell and numerous copies of HIV that repeat the process in other T cells. 

An HIV infection can lead to a weakened immune system, which can then make you vulnerable to opportunistic infections. Fortunately, treatments called antiviral medications are available to help treat and prevent HIV. 

How does PrEP work?

You probably know what PrEP already is. It is available as Truvada or Descovy, which both contain similar ingredients—tenofovir and emtricitabine. But, how exactly does PrEP work in the body?

PrEP acts as a protective barrier around the CD4 helper or T cells. Both tenofovir and emtricitabine are nucleoside reverse transcriptase inhibitors (NRTIs). They block the HIV reverse transcriptase enzyme from working to create copies of the virus. PrEP medication stays inside the T cells and acts as a guard to keep HIV from invading and replicating itself.

How long does PrEP take to work?

While PrEP starts to be absorbed into the body’s immune cells immediately, it takes time for it to work with maximum effectiveness. So, how does PrEP work after several days? It can take 7 days for PrEP to protect against HIV after anal sex. It can take up to 21 days for PrEP to protect against HIV after vaginal sex or injection drug use. 

PrEP medication doesn’t stay inside the immune cells forever. For this reason, it’s important to take the medication daily for optimal protection. Because it isn’t effective enough to treat an HIV infection alone, PrEP should only be used if you are HIV negative before starting to take it.

Does PrEP stop transmission of HIV?

Yes, PrEP helps stop the transmission of HIV. However, it does not treat an existing HIV infection. If you already have HIV, you may be prescribed multiple antiviral drugs to treat the infection. The goal of treating HIV with antiviral medication is to decrease the amount of virus in the blood (viral load) to undetectable levels. A healthcare provider may monitor CD4 levels to track how well treatment is working. 

PrEP is not a vaccine, and it does not protect against other viruses like HPV or COVID-19. There is no evidence to suggest that PrEP can interact with vaccines like the COVID-19 vaccine. 


Is PrEP an antibiotic?

How does PrEP work for bacterial infections? The fact is it doesn’t since PrEP is not an antibiotic. It does not protect against infections caused by bacteria. Ideally, you should use PrEP in combination with other protective methods like condoms to lower the risk of getting HIV and other STIs. Condoms can help decrease the risk of bacterial infections like chlamydia, gonorrhea, and syphilis.

How well does PrEP work?

PrEP is over 90% effective when used correctly. It’s important to take PrEP as directed for maximum benefits. There are different ways to take PrEP, but it’s important to make sure you don’t miss or skip a dose according to your specific plan.

DeliverDose is here to help

If you’re looking for PrEP medicine, DeliverDose can help you. DeliverDose partners with trusted manufacturers to provide high-quality, authentic PrEP medicine. Rest assured, you’re getting the medication you need. You can get affordable PrEP medication shipped straight to your door. Shipping is free and comes in discreet packaging to protect your privacy. 

Get generic Truvada (Tenof-EM) or generic Descovy (Tafero-EM) from DeliverDose. 

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