CDC Yellow Book

Health Care Workers


Health care workers practicing outside the United States may face unique health hazards. Numerous infectious risks are associated with patient contact or handling clinical specimens. Various types of health care workers may be at risk:

  • Physicians, nurses, and other ancillary clinical staff providing care in international settings, including, clinics, hospitals, and field locations
  • Medical students and other health trainees participating in clinical rotations overseas
  • Others working in clinics, hospitals, or laboratories, including researchers, laboratory technicians, ancillary staff, and public health workers

Health care workers in all settings are at risk for exposure to numerous infectious diseases, including infections spread through blood and bodily fluids (such as HIV or hepatitis B) or through airborne or respiratory droplet routes (such as tuberculosis [TB] or influenza). Risks vary depending on the duties of the worker, the geographic location, and the practice setting. Increased risks are due to multiple factors including the following:

  • Less stringent safety regulations or infection control standards
  • Limited availability of personal protective equipment (PPE) or safety-engineered devices
  • Unfamiliar practice conditions or equipment
  • Challenging practice conditions that can prevent providers from adhering to standard precautions (such as extremely resource-limited settings, natural disasters, or conflict zones) (see Box 8-03, Health care workers in extreme circumstances)
  • Unfamiliar medical procedures
  • High prevalence of transmissible infections (such as HIV, hepatitis B, hepatitis C, or TB)
  • Potentially high infectious burden and increased transmission risk from source patients (such as high HIV viral loads in untreated patients)
  • Limited resources for evaluation and treatment after exposure to bloodborne pathogens
  • Potential for outbreaks of uncommon infectious diseases that are transmissible in health care settings (such as Middle East respiratory syndrome [MERS] or viral hemorrhagic fevers)
  • Increased psychological stress resulting from practicing in resource-limited settings, isolated areas, and long-term assignments


In addition to vaccinations specifically indicated for the country visited, all health care workers should be up-to-date on all routine and recommended vaccinations (or have documented immunity). These include the following:

  • Measles, mumps, and rubella
  • Influenza
  • Varicella
  • Tetanus, diphtheria, and pertussis
  • Hepatitis B
  • Other age-appropriate vaccines or those appropriate for travelers with certain underlying medical conditions (such as pneumococcal vaccine)

For hepatitis B, postvaccination serologic testing is recommended for health care workers; of people who do not respond to a primary vaccine series, 25%–50% respond to an additional vaccine dose, and 44%–100% respond to a 3-dose revaccination series. Inactivated polio vaccine (given as an adult booster dose) or meningococcal vaccine may be indicated for specific locations experiencing high incidence or outbreaks of these infections. Providers should consult country-specific recommendations and travel alerts on the CDC Travelers’ Health website ( for updated vaccination recommendations.

Regular screening for latent TB infection with tuberculin skin test or interferon-γ release assay is recommended for health care workers, and pre- and post-travel testing is particularly important when the provider is working in a country with a high prevalence of TB infection or in a setting of high TB exposure, such as in prisons (see Chapter 3, Tuberculosis). Routine vaccination of health care workers with bacillus Calmette-Guérin (BCG) is not recommended in the United States; however, BCG vaccination may be considered for some health care workers who will work in settings with high TB transmission risk and a high prevalence of strains resistant to isoniazid and rifampin. Baseline testing for HIV and hepatitis C before travel is not routinely recommended, although it should be considered if risk of exposure will be high and reliable testing will not be available at the destination in the event of an exposure.

Box 8-03. Health care workers in extreme circumstances

Health care workers regularly provide care in a range of extreme circumstances, which may be characterized by limited or absent medical and public health infrastructure, lack of fundamental hygiene supplies (such as soap and water for handwashing), increased infectious disease transmission, extreme environmental conditions, and high levels of violence. Violent attacks on humanitarian workers have increased substantially in the past 20 years, and kidnappings of aid workers increased 400% from 2002 through 2012.

Because of the increased risks and consequences of severe disease or injury, adequate prevention and preparation are essential. Health problems for the health care worker can have serious implications, not only for the person but also for those groups that depend on the health care worker for care. Detailed instructions on how to prepare for travel or work in developing countries or humanitarian environments is covered in detail in other sections, but additional key considerations include the following:

  1. Reliable communication equipment: usually satellite phone, ensuring service provider contract for duration of the mission. Consider portable solar recharging capabilities unless power supply is guaranteed, which is rare in most extreme circumstances.
  2. Evacuation insurance and plan: depending on the deploying organization, evacuation insurance (see Chapter 2, Travel Insurance, Travel Health Insurance, & Medical Evacuation Insurance) and a detailed evacuation contingency plan may or may not be provided. Both are critical, and the health care worker should be familiar with all details.
  3. The health care workers’ health: providers’ health should be monitored closely and treatment initiated early, if necessary. Any indication that a potentially serious condition is not responding to treatment should warrant rapid planning for potential medical evacuation.
  4. Mental health: providers in conflict and disaster zones typically work long hours in dangerous conditions and are exposed to profound suffering. These experiences can be intensely stressful, leading to increased rates of depression, posttraumatic stress disorder, and anxiety. Before deployment, providers should think about coping strategies and, as much as possible, stay in contact with a support network of family and friends.
  5. Chemical warfare: although rare, health care workers may be exposed to chemical warfare agents while caring for patients, as recently documented in Syria. If exposure to these agents is a possibility, antidotes (such as atropine) should be immediately available. [PMID:23917901]

1Connorton E, Perry MJ, Hemenway D, Miller M. Humanitarian relief workers and trauma-related mental illness. Epidemiol Rev. 2012 Jan;34(1):145–55.
2Harmer A, Stoddard A, Toth K. Aid worker security report 2013, the new normal: coping with the kidnapping threat. London: Humanitarian Outcomes; 2013 [cited 2014 Jul 31]. Available from:
3Human Rights Watch, Safeguarding Health in Conflict Coalition. Under attack: violence against health workers, patients, and facilities. 2014 [cited 2014 Jul 31]. Available from:
4 Lyon RM, Wiggins CM. Expedition medicine—the risk of illness and injury. Wilderness Environ Med. 2010 Dec;21(4):318–24.
5 United Nations Mission to Investigate Allegations of the Use of Chemical Weapons in the Syrian Arab Republic. Report on the alleged use of chemical weapons in the Ghouta area of Damascus. Geneva: United Nations; 2013 [cited 2014 Jul 31]. Available from:



Health care workers should consistently follow standard precautions whenever possible. These include the use of PPE such as gloves, gowns, aprons, surgical masks, and protective eyewear. Workers untrained in standard precautions should not participate in clinical activities, handle clinical specimens, or handle contaminated medical equipment. Needlestick injuries are a common mode of percutaneous exposure to bloodborne pathogens, and practices known to increase risk of needlestick injuries, such as recapping syringes or using needles to transfer a bodily fluid between containers, should be avoided. For further details, guidelines, and training materials on standard precautions and PPE, see and

In preparation, traveling health care workers should

  • Ensure they are properly trained for all anticipated procedures, considering the locally available equipment
  • Maintain strict safety standards, even if local standards are less stringent
  • Bring their own supply of PPE or safety-engineered medical devices if they are unsure of local availability
  • Assess the local availability of reliable postexposure prophylaxis (PEP) for HIV, and consider bringing a supply for personal use if unavailable (see HIV PEP, below).

The traveling health care worker should consider the local practice environment, as limited use of PPE or even reuse of equipment that would not be acceptable in the United States is common. Although HIV antiretroviral medications are now available in much of the developing world, traveling health care workers should confirm availability of HIV PEP with their sponsoring institutions in advance of travel, or bring their own supply.


Health care workers are at risk of acquiring numerous airborne and droplet-transmitted infections from patients. Although some of these pathogens are vaccine preventable (such as measles, influenza, and varicella), airborne or droplet isolation precautions for patients suspected of having some respiratory infections are a mainstay of infection control in the United States. These precautions include PPE such as fit-tested N95 respirator masks and negative-pressure isolation rooms for airborne precautions and surgical masks for droplet precautions. Health care workers should inquire about the availability of PPE and isolation facilities when working internationally. Bringing a personal supply of PPE for use during travel might be prudent (see above, PPE and Infection Control).

TB is a particular concern for health care workers working overseas in high-incidence areas; however, routine use of N95 respirators in settings with limited diagnostic capabilities and suboptimal isolation facilities can be difficult. Pre- and post-travel screening for latent TB is recommended for workers traveling to highly endemic countries (see above, Pre-Travel Vaccination and Screening).

Traveling health care workers should be aware that they may encounter patients with unusual or novel pathogens, particularly when working in areas where epidemics have occurred (such as MERS in the Arabian Peninsula or avian influenza in Asia), and they should consult the disease-specific CDC websites at and the CDC Traveler’s Health website ( for updates and infection control recommendations.


Health care workers are at risk for numerous infections transmitted through exposure to blood or bodily fluids via percutaneous, mucous membrane, or nonintact skin exposures. The prevalence of HIV, hepatitis B (HBV), and hepatitis C virus (HCV) infections high in many countries. The global number of HIV infections among health care workers attributable to sharps injuries has been estimated to be 1,000 cases per year. The risk of HIV transmission is approximately 0.3% after a percutaneous exposure to HIV-infected blood and approximately 0.09% after a mucous membrane exposure. Other bodily fluids that may transmit HIV include cerebrospinal fluid, synovial fluid, pericardial fluid, pleural fluid, peritoneal fluid, amniotic fluid, semen, and vaginal secretions. Saliva, urine, sputum, nasal secretions, tears, feces, vomitus, and sweat are not considered infectious for HIV unless they are visibly bloody. Typically, exposures occur as a result of percutaneous exposure to contaminated sharps, including needles, lancets, scalpels, and broken glass (from capillary or test tubes). The risk of infection after percutaneous exposures is considered increased with exposure to larger blood volumes (visible blood on the injuring device, hollow-bore needles, deeper injuries, or procedures that involved direct cannulation of an artery or vein). Skin exposures to potentially infectious bodily fluids are only considered to be at risk for HIV infection if there is evidence of compromised skin integrity (for example, dermatitis, abrasion, or open wound). Higher circulating viral load in the source patient is also thought to increase the risk of transmission, and this can be of particular concern in resource-poor settings where treatment for HIV and viral hepatitis is limited.

Hepatitis B vaccination, standard precautions, PPE, and safety-engineered devices are important preventative measures (see above sections, Pre-Travel Vaccination and Screening and PPE and Infection Control). Numerous other infections have also been transmitted to health care workers via blood or bodily fluids, including many that are uncommon or not endemic in the United States, such as viral hemorrhagic fevers, parasitic infections, and brucellosis.

Health care workers who may have been occupationally exposed to blood or bodily fluids should immediately perform the following steps:

  • Wash the exposed area with soap and water thoroughly. If mucous membrane exposure has occurred, flush the area with copious amounts of water or saline.
  • If possible, assess the HIV and HCV status of the source patient. HBV testing of the source patient may be indicated if the health care worker is not a documented responder to hepatitis B vaccination.
  • Rapid HIV testing of the source patient is preferred. Exposures originating from source patients who test HIV negative are considered not to have HIV transmission risk, unless they have clinical evidence of primary HIV infection or HIV-related disease.
  • Baseline HIV (and potentially HCV and HBV) testing of the exposed health care worker should be performed at the time of the exposure. Seek qualified medical evaluation as soon as possible to guide decisions on HIV PEP (see below).

Postexposure Prophylaxis (PEP)

A number of medication combinations are available for PEP (see the Updated US Public Health Service Guidelines for the Management of Occupational Exposures to HIV and Recommendations for Postexposure Prophylaxis at Expert consultation is important when considering PEP, since regimen choice should be made with consideration of exposed person’s medical history, potential drug interactions, and the possibility of exposure to a drug-resistant strain. When expert advice is not immediately available, the National Clinicians’ Postexposure Prophylaxis Hotline (PEPline) can be reached toll-free at 888-448-4911 (9 am to 2 am Eastern Time daily) for assistance in managing occupational exposures to HIV and hepatitis B and C ( When initiating HIV PEP, it must be started as soon as possible. PEP can be stopped if new information changes the assessment; however, waiting to start PEP until all information is gathered can decrease its efficacy.

Other potentially infectious exposures in the source material should be considered and managed as appropriate. If the health care worker is not a documented serologic responder to hepatitis B vaccination or is incompletely vaccinated, postexposure testing of the source patient and health care worker may be indicated, as well as PEP with hepatitis B immune globulin and vaccination. For further details, see

Postexposure Testing and Counseling

Health care workers with occupational exposure to HIV should receive standard HIV testing as soon as possible after exposure as a baseline, with follow-up testing at 6 weeks, 3 months, and 6 months (follow-up to 4 months is acceptable if a fourth-generation combination HIV p24 antigen-HIV antibody test is used). Health care workers with known or potential exposure to HCV should also have baseline and follow-up testing for HCV. Extended HIV follow-up testing for up to 12 months is recommended for those who become infected with HCV after exposure to a source coinfected with HIV and HCV.

Postexposure counseling and medical evaluation should be provided, whether or not the exposed person receives PEP. During the first 12 weeks after exposure, health care workers should take precautions to avoid secondary transmission (such as abstaining from sexual contact, using barrier contraception, avoiding blood or tissue donations, and breastfeeding, if possible). When PEP is initiated, exposed health care workers should be counseled regarding drug toxicities, drug interactions, and the importance of adherence. Drug side effects are a common reason for PEP discontinuation, although newer regimens have improved tolerability. The emotional consequences of occupational exposures can be substantial and might be further exacerbated by stressors already present in the work environment. Psychological counseling should be considered an essential part of the management of exposures.


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  2. CDC. Healthcare-associated infections (HAIs). Atlanta: CDC; 2014 [cited 2014 Jul 31]. Available from:
  3. CDC. Tuberculosis (TB). Atlanta: CDC; 2014 [cited 2014 Jul 31]. Available from:
  4. Clinicians Consultation Center. Post-exposure prophylaxis (PEP): timely answers for urgent exposure management. San Francisco: UCSF; 2014 [cited 2014 Sep 24]. Available from:
  5. Kuhar DT, Henderson DK, Struble KA, Heneine W, Thomas V, Cheever LW, et al. Updated US Public Health Service guidelines for the management of occupational exposures to human immunodeficiency virus and recommendations for postexposure prophylaxis. Infect Control Hosp Epidemiol. 2013 Sep;34(9):875–92. [PMID:23917901]
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  7. Mohan S, Sarfaty S, Hamer DH. Human immunodeficiency virus postexposure prophylaxis for medical trainees on international rotations. J Travel Med. 2010 Jul–Aug;17(4):264–8. [PMID:20636600]
  8. Schillie S, Murphy TV, Sawyer M, Ly K, Hughes E, Jiles R, et al. CDC guidance for evaluating health-care personnel for hepatitis B virus protection and for administering postexposure management. MMWR Recomm Rep. 2013 Dec 20;62(RR-10):1–19.
  9. Uslan DZ, Virk A. Postexposure chemoprophylaxis for occupational exposure to human immunodeficiency virus in traveling health care workers. J Travel Med. 2005 Jan–Feb;12(1):14–8. [PMID:15996462]
  10. Vaid N, Langan KM, Maude RJ. Post-exposure prophylaxis in resource-poor settings: review and recommendations for pre-departure risk assessment and planning for expatriate healthcare workers. Trop Med Int Health. 2013 May;18(5):588–95. [PMID:23461554]


Henry M. Wu, V. Ramana Dhara, Alan G. Czarkowski, and Eric J. Nilles