Risk of seroconversion for acquired immunodeficiency syndrome (AIDS) in San Francisco health workers

Seroconversion rate among health care workers exposed to HIV-contaminated body fluids: The University of Pittsburgh 13-year experience

BACKGROUND

The studies enumerating the risk of HIV transmission to health care workers (HCWs) as 0.3% after percutaneous exposure to HIV-positive blood, and 0.09% after a mucous membrane exposure, are weakened by dated literature. Our study aims to demonstrate the seroconversion rate after exposure to HIV-contaminated body fluids in a major academic center in the United States.

METHODS

A prospectively maintained database of reported occupational injuries occurring between 2002 and 2015 at an academic medical center was analyzed. Data collected included the type of injury, injured body part, type of fluid, contamination of sharps, involvement of resident physicians, use of postexposure prophylaxis, and patients' HIV, hepatitis B virus, and hepatitis C virus status.

RESULTS

A total of 266 cases were included in the study. Most exposures were caused by percutaneous injuries (52.6%), followed by 43.2% mucocutaneous injuries. Of the injuries, 52.6% were to the hand and 33.5% to the face and neck. Blood exposure accounted for 64.3% of all cases. Of the patients, 21.1% received postexposure prophylaxis. None of the HCWs exposed to HIV-contaminated body fluids seroconverted (seroconversion rate, 0%).

CONCLUSIONS

HIV does not seem to be as easily transmitted by needlestick, laceration, or splash injuries as previously surmised. Further large-scale and multicenter studies are needed for a more accurate estimation of the risk of transmission of HIV in U.S. health care workers.

Estimating per-act HIV transmission risk: a systematic review

BACKGROUND

Effective HIV prevention programs rely on accurate estimates of the per-act risk of HIV acquisition from sexual and parenteral exposures. We updated the previous risk estimates of HIV acquisition from parenteral, vertical, and sexual exposures, and assessed the modifying effects of factors including condom use, male circumcision, and antiretroviral therapy.

METHODS

We conducted literature searches to identify new studies reporting data regarding per-act HIV transmission risk and modifying factors. Of the 7339 abstracts potentially related to per-act HIV transmission risk, three meta-analyses provided pooled per-act transmission risk probabilities and two studies provided data on modifying factors. Of the 8119 abstracts related to modifying factors, 15 relevant articles, including three meta-analyses, were included. We used fixed-effects inverse-variance models on the logarithmic scale to obtain updated estimates of certain transmission risks using data from primary studies, and employed Poisson regression to calculate relative risks with exact 95% confidence intervals for certain modifying factors.

RESULTS

Risk of HIV transmission was greatest for blood transfusion, followed by vertical exposure, sexual exposures, and other parenteral exposures. Sexual exposure risks ranged from low for oral sex to 138 infections per 10,000 exposures for receptive anal intercourse. Estimated risks of HIV acquisition from sexual exposure were attenuated by 99.2% with the dual use of condoms and antiretroviral treatment of the HIV-infected partner.

CONCLUSION

The risk of HIV acquisition varied widely, and the estimates for receptive anal intercourse increased compared with previous estimates. The risk associated with sexual intercourse was reduced most substantially by the combined use of condoms and antiretroviral treatment of HIV-infected partners.

Risk of HIV-1 transmission for parenteral exposure and blood transfusion: a systematic review and meta-analysis

BACKGROUND

The role of iatrogenic transmission within the HIV/AIDS pandemic remains contentious. Estimates of the risk of HIV transmission from injections and blood transfusions are required to inform appropriate prevention policy.

OBJECTIVES

Systematic review and meta-analysis of the literature on HIV-1 infectivity for parenteral transmission and blood transfusion.

REVIEW METHODS

All identified studies with relevant transmission probability estimates up to May 2005 were included.

STATISTICAL METHODS

When appropriate, summary estimates for accidental percutaneous and blood product exposures were derived.

RESULTS

Infectivity estimates following a needlestick exposure ranged from 0.00 to 2.38% [weighted mean, 0.23%; 95% confidence interval (CI), 0.00-0.46%; n = 21]. Three estimates of infectivity per intravenous drug injection ranged from 0.63 to 2.4% (median, 0.8%); a summary estimate could not be calculated. The quality of the only estimate of infectivity per contaminated medical injection (1.9-6.9%) was assessed. Instead we propose a range of 0.24-0.65%. Infectivity estimates for confirmed contaminated blood transfusions range from 88.3 to 100.0% (weighted mean, 92.5%; 95% CI, 89.0-96.1%; n = 6).

CONCLUSIONS

Infectivity estimates for infected blood transfusions are larger than for other modes of HIV transmission. Few studies on transmission risk per contaminated injection were found. However, transmission risk per needlestick injury, where needles are more likely to be rinsed or disinfected between recipients (especially for medical injections), may be representative of non-intravenous medical injections and lower than the risk from intravenous injections, which are likely to be deeper and to involve more fluids. Further work is needed to better estimate transmission probability related to contaminated injections and its likely contribution to overall HIV transmission.

Risk of infection from needle reuse at a phlebotomy center

OBJECTIVES

This study determined infection risk for HIV, hepatitis B virus (HBV), and hepatitis C virus (HCV) from needle reuse at a phlebotomy center that possibly exposed 3810 patients to infection.

METHODS

We used a model for the risk of infection per blood draw, supplemented by subsequent testing results from 1699 patients.

RESULTS

The highest risk of transmission was for HBV infection: 1.1 x 10(-6) in the best case and 1.2 x 10(-3) in the (unlikely) worst case. Subsequent testing yielded prevalence rates of 0.12%, 0.41%, and 0.88% for HIV, HBV, and HCV, respectively, lower than National Health and Nutrition Examination Survey III prevalence estimates.

CONCLUSIONS

The infection risk was very low; few, if any, transmissions are likely to have occurred.

HIV infection in healthcare workers. How great is the risk? What can be done before and after exposure?

Healthcare workers know that there is a risk of HIV infection through exposure to AIDS patients. In both hospital and office settings, physicians have the opportunity to set standards and promote education about the degree of risk, effective precautions, and postexposure testing, prophylaxis, and treatment. Drs Henry and Thurn share the latest findings and offer policy recommendations based on their own experience.