HBV, HCV and HIV: What’s the Difference?

Ask somebody which infection they would most dread catching from a needlestick and almost everyone names the same one. It's the answer four decades of public awareness built, and it isn't the one that most often gets passed on at work.

That gap between what people fear and what actually transmits is worth closing, because it puts the effort in the wrong place. The virus that spreads most readily in a workplace is also the one you can be vaccinated against — which means the most useful thing on this page is something you can act on rather than something to worry about.

The three, side by side

Three viruses account for most occupational bloodborne risk. They're grouped together because of how they travel, not because they're alike — and the differences are where all the useful information lives.

Two rows are worth reading against each other. The one that transmits most readily is the one with a vaccine — which is the single most actionable fact on this page. And the one people fear most is the one that transmits far less readily than it does, and survives worst outside the body.

It's worth seeing how far apart those two ends actually are. After a single needlestick from a known-positive source, the risk of infection runs roughly:

• Hepatitis B — the highest of the three by a wide margin, and in an unvaccinated person it can reach the tens of percent. In somebody vaccinated, with immunity on record, it drops to virtually nothing.

• Hepatitis C — around two in a hundred by the long-standing estimate, with more recent data putting it lower.

• HIV — around three in a thousand, and lower again for a splash to the eye or mouth rather than a puncture.

Those are approximate, they describe a needlestick from a source known to be infected, and no single exposure is well described by an average. Read them for the gradient rather than the arithmetic — and read it for the shape that isn't in doubt: hepatitis B sits far above the other two, HIV sits very low, and both hepatitis viruses are the reason a needlestick is taken seriously at all. The two lower figures are close enough to each other, and moving enough as data improves, that ranking them against one another isn't something to do with a page like this.

And notice what that top figure is conditional on. The tens-of-percent number describes somebody unvaccinated. It's the one rung on this ladder that a person can move for themselves, in advance, which is what the next section is about.

Hepatitis B — the one that should worry you most

It leads because it earns the position. Of the three it's the most readily transmitted in an occupational exposure, and it's the one with real environmental staying power: at least seven days on a surface, still capable of causing infection. That's the fact that makes cleaning a spill properly a genuine control rather than tidiness — and it's why contact time on a disinfectant matters.

Many adults who are infected clear it themselves and are left immune. Some don't, and a long-term infection carries real liver consequences over years. Which of those happens isn't something you influence after the fact.

If nobody has ever offered you that vaccine and blood is part of your job, that's a gap in what your employer is required to provide — and it's worth raising as a question rather than assuming somebody decided you didn't need it.

Hepatitis C — quiet, and now curable

Hepatitis C is the one whose story has changed most, and anything you read from more than a decade ago will understate it badly. It's now curable — a course of antiviral tablets clears the virus in the great majority of people treated. That's a genuinely different situation from the one this disease occupied when most workplace training material was written.

What hasn't changed is that it's quiet. Many people carry it for years with no symptoms, which means it's found by testing rather than by feeling unwell — and that's the argument for baseline and follow-up testing after an exposure rather than waiting to see how you feel.

There's no vaccine, and there's no preventive treatment to take immediately after an exposure the way there's for the other two. The response is monitoring, and treating early if it's found — which works, and depends entirely on somebody knowing to look.

HIV — the one everyone thinks of first

This is where the proportion needs correcting, and it's worth being careful about what the correction does and doesn't say. HIV is a serious infection. It's also transmitted far less readily than hepatitis B through an occupational exposure — roughly a hundredfold difference per needlestick — and it survives poorly outside the body, so dried blood on a surface is a very different proposition for this virus than for hepatitis B.

Preventive medication after an exposure exists and works, and it's time-sensitive — which is the practical reason the reporting step in the exposure procedure is worth doing the same day rather than the next one. Treatment has transformed the outlook for people living with HIV, to the point where the picture most people carry in their heads is decades out of date.

One part of that's worth stating plainly, because it changes what a positive result would mean: treatment can suppress the virus to undetectable levels, which also makes transmission dramatically less likely.

If this is the virus you've been most worried about, that isn't ignorance — it's the accurate result of a very effective public awareness effort, one that was right about the disease and never made any claim about how the three compare in a workplace.

How they actually spread

All three travel the same way: blood or certain other body fluids reaching you through a route that lets them in. The routes are specific.

• Parenteral — under the skin. A needlestick, a cut from a contaminated instrument, a bite that breaks skin.

• Mucous membrane — the eye, the mouth, or another membrane. A splash is enough.

• Non-intact skin — a cut, a graze, cracked or broken skin, dermatitis.

Intact skin isn't on that list, and its absence is the whole architecture of how this is managed. Unbroken skin is a barrier, which is why the precautions are organized around routes rather than around people — and why a cut on your own hand quietly changes the situation you're working in.

Things that don’t pass it on

This is here because people reach a page like this in the days after something happened, and the mind fills the gaps unhelpfully. None of these three viruses is transmitted by:

• Casual contact — shaking hands, hugging, sitting beside someone

• Sharing a workspace, a kitchen, a bathroom or a toilet seat

• Coughing, sneezing, or breathing the same air

• Sharing crockery or cutlery

• Insect bites

• Donating blood

Which is worth stating precisely because the precautions can feel like they imply otherwise. They do not. The rule is about blood and about routes — it is not a reason to treat a colleague differently, and it never was.

The others

These three are named in workplace training because they're the ones occupational exposure realistically involves, not because the list ends there. Others exist — including syphilis, malaria and brucellosis — and they're far less likely to arise this way.

That isn't a footnote so much as the argument for the whole approach. If the rule were "protect yourself against these three", it would need updating every time the list changed. Treating all blood as infectious doesn't depend on knowing what is in it — which is exactly why that's the rule.

Put it into practice

Training scenario:

Four days ago you caught your hand on something in a waste bag at work. You washed it, you reported it that afternoon, you had blood drawn and a conversation with a nurse, and you were told you'd be tested again in a few weeks. You've done everything you were supposed to do. It's now Sunday night, you can't sleep, and you've been reading things on your phone for two hours. You can't remember whether anyone mentioned hepatitis at all — you only remember asking about HIV.

Walking it through:

The fact most likely to change how tonight feels is the proportion: the virus you asked about transmits far less readily than the one nobody mentioned, and it survives poorly outside the body — a scratch from something in a bag is a long way from the worst case your phone has been showing you. The evaluation you already had is the process working, and follow-up testing weeks later is the normal shape of it rather than a sign anybody is worried.

The question worth asking on Monday is the one you didn't think to ask: are you vaccinated against hepatitis B, and if not, why were you never offered it? That's the one of the three where something could have been done in advance, and it's the one that would still be worth sorting out — not for this incident, but for the next four years of doing this job.

And the honest part: nothing on this page makes four days of waiting comfortable. What it can do is stop the waiting being spent on the wrong virus.