What Are the 3 Most Common Bloodborne Pathogens?

The three bloodborne pathogens that workplace training focuses on are hepatitis B virus (HBV), hepatitis C virus (HCV) and HIV. All three are viruses carried in blood, and all three reach a new person the same way: infected blood gets in through a cut, a needle or a mucous membrane such as the eyes or mouth. HIV is the one people fear most, yet it is the least likely of the three to spread after a needlestick. Hepatitis B is the most contagious, and it is the only one with a vaccine.

How Likely Each Virus Is to Spread After a Needlestick

These figures describe the chance of infection from a work exposure when the source person is infected:

Hepatitis B spreads so much more easily than HIV because infected blood typically carries far more hepatitis B virus per drop. Even a tiny, invisible amount of blood can be enough. HIV is fragile outside the body by comparison, while hepatitis B is tough. Because you usually can’t tell whose blood carries a virus, training treats all blood as potentially infectious.

The 18% to 30% range applies to people with no immunity. A completed hepatitis B vaccine series protects most people, so a worker with confirmed immunity faces very little hepatitis B risk from a stick.

Some exposures are worse than others. The worst case for hepatitis B is a hollow, blood-filled needle from a highly infectious patient, which infects 37% to 62% of unvaccinated people.4Centre for Health Protection. Recommendations on the Management and Postexposure Prophylaxis of Needlestick Injury or Mucosal Contact to HBV, HCV and HIV A deep stick from a needle just used in a vein carries far more risk than a shallow scratch. For HIV, a larger amount of blood and a source person with a high level of virus in their blood raise the risk.5PubMed. The risk of needle stick accidents during surgical procedures: HIV-1 viral load in blood and bone marrow

It’s easy to misread 0.3%. It means about 3 in 1,000 sticks from an HIV-positive source cause infection, not that every needlestick carries that risk. If the source person is on effective treatment, the risk is lower still. Low risk is still a reason to report, because treatment works best when it starts early.

All of these figures assume the source is infected, and most needlesticks involve someone who carries none of the three. A needle found in the trash or a park is generally lower risk than one just pulled from a patient’s vein, because the blood inside is old and the amount is small. Low is not zero, though. Hepatitis B can survive in dried blood, so a found needle still calls for washing, reporting and being assessed.

How Hepatitis B, Hepatitis C and HIV Survive and Spread

Hepatitis B can stay infectious on surfaces for at least 7 days.6PubMed Central. The Heat Stability of Hepatitis B Virus: A Chronological Review From Human Volunteers and Chimpanzees to Cell Culture Model Systems In liquid at room temperature, it keeps most of its infectivity for weeks.7PubMed Central. High Environmental Stability of Hepatitis B Virus and Inactivation Requirements for Chemical Biocides A dried blood spot on a counter or tool can therefore still pass on the virus. Clean up any blood with a disinfectant even when it has dried, and wear gloves while you do it.

Outside hospitals, shared and unsafe needles drive much of the spread. Sharing needles to inject drugs is a leading cause of new hepatitis C infections.8PubMed Central. Risk Factors of Hepatitis C Virus Infection in Drug Users From Eleven Methadone Maintenance Treatment Clinics in Xi’an, China Worldwide, about 43% of new hepatitis C infections could be prevented by removing the extra risk from injecting drugs, and about 79% in wealthy countries.9PubMed Central. The contribution of injecting drug use as a risk factor for Hepatitis C virus transmission globally, regionally, and at country level: a modelling study Medical care can be a route too: in many lower-income countries, reused or unsterile medical injections account for 20% to 80% of new hepatitis B infections.10PubMed Central. Unsafe injections in the developing world and transmission of bloodborne pathogens: a review Hepatitis B and HIV also pass through sex and from mother to baby at birth.11Morbidity and Mortality Weekly Report. Hepatitis B Virus: A Comprehensive Strategy for Eliminating Transmission in the United States Through Universal Childhood Vaccination

Hepatitis C is different on that point. It spreads through sex far less often than hepatitis B or HIV, because blood-to-blood contact is its main route. The risk rises when sex involves blood or when HIV is also present.

Blood is the main concern for all three. Semen and vaginal fluids can carry hepatitis B and HIV. Urine, vomit and saliva matter mainly when they contain visible blood, and training treats any fluid with visible blood as infectious.

Everyday contact is not a worry. Hugging, sharing food, toilet seats and coughing do not spread any of the three, and sweat and tears are not considered a real risk. What does carry risk is anything that moves a trace of blood from one person to another. Sharing razors, toothbrushes or nail clippers can do it, because nicks and bleeding gums leave amounts of blood too small to see. Hepatitis B and C are the usual worries with shared grooming items, since they are hardier and more common than HIV.

The same logic applies to tattoos and piercings. Any tool that punctures skin can carry blood to the next person if it is reused without proper sterilization. Licensed studios use single-use needles and sterilize reusable equipment, so the risk comes mainly from unlicensed settings and home setups.

What to Do Right After a Blood Exposure

Wash a needlestick or cut with soap and water, and flush splashes to the eyes, nose or mouth with water. Then report the injury to your supervisor or occupational health right away. Treatment after exposure, often called PEP, works best when it is started within hours.

Timing matters most for HIV. The usual limit for starting medicines is about 72 hours, so a stick late in a shift should not wait until morning. If your workplace has no occupational health service at that hour, go to an emergency department and say it was a blood exposure at work. Reporting quickly also lets the clinic arrange testing and paperwork while the timing still counts.

For hepatitis B, people without immunity get a shot of hepatitis B antibodies, called HBIG, plus the vaccine.12Hepatitis B Online. Core Concepts – Occupational HBV Postexposure Prophylaxis In one report, infection after work exposures was 4% with the vaccine plus HBIG versus 11% with HBIG alone.13Hepatitis B Online. Core Concepts – Occupational HBV Postexposure Prophylaxis Treatment has still prevented infection when given a little after 24 hours.14PubMed Central. Occupational exposure to Hepatitis B virus, disease burden and pathways for postexposure prophylaxis management: recommendations for healthcare workers in highly endemic settings The window is longer than for HIV, but HBIG started more than 7 days after exposure hasn’t been tested, so don’t wait.15Hepatitis B Online. Core Concepts – Occupational HBV Postexposure Prophylaxis

HIV PEP is a course of HIV medicines, and guidelines cover work, sexual and community exposures.16PubMed. UK guideline for the use of HIV post-exposure prophylaxis 2021 Infection was rare among people given PEP, about 6 in 10,000, mostly when people stopped early or were exposed again.17PubMed. Systematic review of clinical trials and cohort studies evaluating HIV post-exposure prophylaxis (PEP) regimens to inform updated Canadian guidelines That is why finishing the full course matters. Most people do finish it.18PubMed. Systematic review of clinical trials and cohort studies evaluating HIV post-exposure prophylaxis (PEP) regimens to inform updated Canadian guidelines

Hepatitis C has no preventive shot or pill after exposure. Instead, follow-up blood tests check whether infection develops. If it does, modern pills cure most cases, as covered below.

Your employer may ask to test the source person’s blood, usually with that person’s consent; some states have laws allowing testing after certain exposures. A negative result can allow HIV treatment to be stopped early, sparing you a full course of medicine.

Follow-up begins with a baseline blood test soon after the exposure. Repeat tests over the following months then check for each virus. During this period you are advised to use condoms and not to donate blood. Keep copies of the workplace exposure paperwork, since it may matter for workers’ compensation.

How Serious Each Infection Is Long Term

Long-term hepatitis B can cause cirrhosis, which is severe liver scarring, and liver cancer.19PubMed Central. Hepatitis B Virus-Associated Hepatocellular Carcinoma Each year about 2% to 6% of people with long-term hepatitis B develop cirrhosis.20PubMed Central. Molecular Mechanisms Driving Progression of Liver Cirrhosis towards Hepatocellular Carcinoma in Chronic Hepatitis B and C Infections: A Review Of those with cirrhosis, about 2.3% a year develop liver cancer.21PubMed Central. Molecular Mechanisms Driving Progression of Liver Cirrhosis towards Hepatocellular Carcinoma in Chronic Hepatitis B and C Infections: A Review Antiviral treatment lowers that cancer risk.22PubMed Central. Molecular Mechanisms Driving Progression of Liver Cirrhosis towards Hepatocellular Carcinoma in Chronic Hepatitis B and C Infections: A Review

Long-term hepatitis C usually scars the liver slowly.23PubMed Central. Fibrosis progression in chronic hepatitis C virus infection Some people barely progress while others scar quickly.24PubMed Central. Fibrosis progression in chronic hepatitis C virus infection Over several years, about 4 in 10 people worsened and about 1 in 4 improved.25PubMed. Progression of fibrosis in chronic hepatitis C

Once scarring is severe, the liver cannot do its work as well, and advanced cases can bring fluid buildup, bleeding and confusion. Early scarring can sometimes improve when the virus is controlled or cleared, which is why catching infection early matters.

HIV works differently. It infects and destroys CD4 cells, the immune cells that coordinate the body’s defense.26PubMed Central. Pathophysiology of CD4+ T-Cell Depletion in HIV-1 and HIV-2 Infections Untreated, the immune system weakens over years until infections it would normally fight take hold, which is AIDS.27PubMed Central. CD4+ cell depletion in HIV infection: mechanisms of immunological failure HIV medicines quickly raise CD4 counts and reverse that weakening.28PubMed Central. Pathophysiology of CD4+ T-Cell Depletion in HIV-1 and HIV-2 Infections

All three infections can cause no symptoms for years, and liver damage often isn’t felt until it’s advanced. That is why testing after an exposure matters even if you feel fine.

Can They Be Cured or Prevented

Modern hepatitis C pills cure more than 95% of people in 8 to 12 weeks.29PubMed Central. Treatment of hepatitis C virus infection with direct-acting antiviral agents: 100% cure? Real-world cure rates are 90% to 100%, including people with advanced liver disease.30PubMed Central. Hepatitis C virus cure with direct acting antivirals: Clinical, economic, societal and patient value for China31PubMed Central. Chronic Hepatitis C in the Direct-Acting Antivirals Era: Carcinogenesis and Clinical Implications

Cure means no virus can be detected in the blood at a test taken at least 12 weeks after treatment ends. A cured person no longer carries or spreads the virus, and liver inflammation typically settles. Cure does not make anyone immune, though, so reinfection is possible after another exposure. People with advanced scarring before treatment still need liver checks afterward, because their cancer risk does not drop to zero.

The hepatitis B vaccine is the only vaccine against any of the three. Babies of infected mothers given the vaccine plus HBIG at birth are 85% to 95% protected from lifelong infection.32Morbidity and Mortality Weekly Report. Hepatitis B Virus: A Comprehensive Strategy for Eliminating Transmission in the United States Through Universal Childhood Vaccination Workers at risk should get vaccinated, and US employers must offer the vaccine free to exposed staff.

Hepatitis B itself is managed rather than cured. Medicines suppress the virus but rarely clear it completely, so many people take treatment long term. Regular liver checks catch damage or cancer early.

HIV has no cure or vaccine yet. Daily treatment lets most people live a near-normal lifespan, and treatment that keeps the virus undetectable prevents sexual spread. People at ongoing risk can also take pre-exposure pills to protect themselves.

Protecting Yourself Day to Day

Needles with built-in shields or retracting tips, called safety-engineered devices, substantially reduce needlestick injuries.33PubMed. Reducing needlestick injuries through safety-engineered devices: results of a Japanese multi-centre study Using them when drawing blood was linked to 74% fewer needlesticks.34Infection Control & Hospital Epidemiology. Role of Safety-Engineered Devices in Preventing Needlestick Injuries in 32 French Hospitals In US workplaces, employers must review and adopt safer devices every year.35Occupational Safety and Health Administration. Bloodborne Pathogens and Needlestick Prevention

Wear gloves, and add eye protection when splashes are possible. Never recap needles by hand. Drop sharps straight into a puncture-proof container that isn’t overfilled.

Keep that container within arm’s reach of where needles are used. Seal and replace it when it is about three-quarters full, since overfilled containers cause sticks when someone pushes sharps down. Never reach into a container or pick up a needle with your fingers; use tongs, or a brush and dustpan if one is on the floor. At home, use an approved sharps container or a heavy plastic bottle with a screw lid, and follow local disposal rules.

For a blood spill, put on gloves before touching anything. Soak up the blood with disposable towels, then disinfect with an approved product or a fresh bleach solution and leave it on as the directions say. Bag the waste, and wash your hands after removing the gloves.

Outside work, syringe programs that provide clean needles are linked to less HIV and hepatitis C among people who inject drugs.36archive.cdc.gov. Access to clean syringes In New York, HIV among people who inject drugs fell from 50% to 17% after syringe exchange was legalized.37archive.cdc.gov. Access to clean syringes Never share needles, syringes or other injecting equipment.