How does PrEP work?

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3 questions really: How does PrEP work? Is it taken every day? If we can create medications to prevent viruses like HIV, why isn’t there a medication to prevent the common cold?

In: Biology

2 Answers

Anonymous 0 Comments

PrEP is a combination of some of the same drugs used to treat HIV, but instead taken preventatively. It’s taken every day. In a person who is HIV+, the drugs work by making it more difficult for the virus to replicate, and thus reducing the person’s viral load. Taken as a preventative, it can keep the virus from gaining a foothold in the first place, and thus preventing it from establishing an infection. It’s not a cure or a magic shield, and while it’s very effective, it’s not perfect.

We don’t have a medication for the common cold for many reasons. First, is that the common cold is not a single virus, but hundreds of different viruses that cause similar symptoms, and they all mutate rapidly. There’s simply no way to make a single medication that can protect against the hundreds of viruses out there, and even if there was, they mutate so fast that the medication would be useless after a while. Second is that medications have side effects. PrEP is not without side effects. It’s not given to just anyone; it’s given to people who have a higher risk of contracting HIV, because for the average person, the side effects do not warrant it. Third, a cold is simply not that bad. You feel kind of crappy for a few days and that’s it. Everyone gets colds. You suck it up, eat some soup, sleep, and move on with your life. Using antiretroviral medications for a cold is like using a nuclear weapon on your house because you found some ants in your kitchen.

Anonymous 0 Comments

1. All the current forms of PrEP (and PEP, which are similar drugs taken AFTER potential exposure to HIV) work the same say: the drugs inhibit the virus’s ability to reproduce by interfering with an enzyme called retro transcriptase, which the virus uses to trick the cell into producing new copies of the virus. Without the enzyme, or enough of it, the viruses can’t multiple and infect other cells and therefore can’t establish a permanent infection.
2. It should be taken every day. With daily use, protection rates are higher than 99%. Taken only 6 days a week, the protection rate drops to 96%, and becomes much less effective with each further missed dose.
3. Developing a form of PrEP for the common cold would take a lot of time and money and require patients to take (probably very expensive) drugs on a daily basis. PrEP does have side effects, mostly minor like headaches and nausea, but some people have reported more serious potential side effects. The same would be true of a common cold-PrEP, and the cold is not a dangerous infection worth the effort and risk of either developing a preventive drug or taking that drug.