Transfusion medicine
Transfusion transmitted disease
Viruses
Author: Huy P. Pham, M.D., M.P.H.
Last author update: 1 October 2011
Last staff update: 12 March 2025
Copyright: 2002-2025, PathologyOutlines.com, Inc.
PubMed Search: Transfusion transmitted[TI] viruses[TIAB]
Cite this page: Pham HP. Viruses. PathologyOutlines.com website. https://www.pathologyoutlines.com/topic/transfusionmedviruses.html. Accessed April 1st, 2025.
CMV
- 50 - 85% of U.S. population is CMV+; 50% of U.S. donors are CMV seropositive, compared with 93% in Ghana (Ghana Med J 2006;40:99)
- Seroconversion rate is 1% per year
- CMV is almost always latent in immunocompetent adults; CMV virus is latent in leukocytes
- Leukoreduction reduces risk of CMV transmission
- Leukoreduced blood products are generally considered equivalent to CMV negative products
- CMV can cause pneumonitis, hepatitis, retinitis or organ failure in immunocompromised recipients, who should get CMV negative or leukoreduced blood components (Bone Marrow Transplant 2005;36:499, Transfus Med Rev 2005;19:181)
Hepatitis B
- Hepatitis B is a DNA virus, which is transmitted parenterally, sexually, perinatally
- Vaccination of infants and high risk adults led to a decrease in U.S. incidence from 260,000 to 60,000 new infections/year
- Vaccinated children may be susceptible in endemic areas (J Hepatol 2006;44:39)
- Hepatitis B infection can result in acute infection with subsequent clearance of virus and immunity OR chronic infection with persistent viremia
- Previously, hepatitis B transmission was most serious transfusion transmitted disease risk but due to serologic testing, risk of transfusion transmitted HBV is now 1:205,000 among repeat donors and 1:144,000 among all donors in the U.S., 1 per 1.3 million units in Australia (Intern Med J 2005;35:592), 1 per 640,000 in France (Transfus Clin Biol 2005;12:239), 1 per 150,000 in Canada (Transfusion 2007;47:316), 1 per 17,500 in Shenzhen, China (Transfusion 2007;47:529), 1 per 1,500 in Mexico (Rev Invest Clin 2006;58:101)
- Transfusion transmitted hepatitis B may be over reported or under reported
- To reduce rates even further, vigilance for errors and donor selection may be as important as further testing (Euro Surveill 2005;10:17)
- Value of nucleic acid testing (NAT) is controversial (helpful in high prevalence area - Vox Sang 2006;91:1, Transfusion 2005;45:1247; not helpful in low endemic areas, Mol Diagn Ther 2006;10:77)
- In U.S., minipool NAT testing does not decrease the window period significantly
- In U.S., blood banks use sensitive HBsAg and anti-HBc tests
- In most of the world, prevalence of anti-HBc is > 10% and use of HBc antibody test may exclude many otherwise healthy donors (J Clin Virol 2006;36:S33)
- Pathogen inactivation has eliminated transmission in U.S. licensed plasma derivatives since 1985; however cannot be used for cellular components (Arch Pathol Lab Med 2007;131:719)
- Only one confirmed transfusion related case in U.S. in 2003; false positive seroconversions may occur due to administration of immunoglobulin (Dtsch Med Wochenschr 2006;131:1325)
- Microarray multiplex assay may be useful to detect Hepatitis B, C and HIV (Biochem Biophys Res Commun 2007;356:1017)
Hepatitis C
- Hepatitis C virus is an RNA virus
- Transmitted parenterally, especially through blood transfusions (before testing) and intravenous drug use
- Historical risk for "non-A, non-B hepatitis" was 7% from volunteer donated blood and 28% from commercial blood
- 9% of Chinese patients with HCV due to unscreened blood have developed cirrhosis after a mean of 13 years (Zhonghua Gan Zang Bing Za Zhi 2006;14:199)
- Recommended to offer screening to patients (particularly children) who received blood products in 1992 (U.S.) or previously, when blood was not screened for HCV (Acta Paediatr 2007;96:1050, Transfusion 2007;47:615, Transfusion 2005;45:1020)
- Serologic testing and nucleic acid based testing have reduced risk, although developing countries may not screen (J Hepatol 2006;45:607)
In the U.S.:
- In 1970s, 10% of blood transfusion recipients had evidence of hepatitis C
- With current NAT testing, the risk of transfusion transmitted hepatitis C infection is 1:1.4 million products
- Documented breakthrough cases from nonreactive nucleic acid testing components are rare (Lancet 2000;355:41)
- Yield of HCV look back in Canada is likely zero when prior donations were tested by second or third generation EIA (Transfusion 2006;46:690)
- Identified in 1 per 250,000 donors in U.S. (Arch Pathol Lab Med 2007;131:702)
- Donors are usually asymptomatic
- Risk factors are injection drug use, hemodialysis, incarceration, receipt of blood products prior to HCV testing
- Also ozone enriched transfusion of autologous blood in Italy (Infect Control Hosp Epidemiol 2005;26:762)
- Antigen positive donors may not seroconvert (Transfusion 2000;40:1280)
- Pathogen inactivation has eliminated transmission in U.S. licensed plasma derivatives since 1985; however technique cannot be used for cellular components (Arch Pathol Lab Med 2007;131:719)
- References: Medscape: Pediatric Hepatitis C [Accessed 30 October 2017], Albert and Mary Lasker Foundation: Hepatitis C Virus and Its Detection in Blood for Transfusions [Accessed 30 October 2017]
HIV
- HIV is a lentivirus, a subgroup of the retrovirus family
- HIV is transmitted through sexual contact, childbirth, breast feeding and parenteral exposure to blood
- HIV transmission by blood products is efficient: infectivity is 90 - 100% for contaminated blood versus 0 - 2% for needlestick injuries (AIDS 2006;20:805)
- Transfusion associated HIV cases usually have an acute viral syndrome; if untreated, progress to AIDS in 10 years
- HIV1 and HIV2 both can cause AIDS; HIV2 is rare in U.S., with NO reported cases of transfusion transmission in U.S.
- Possibility of transfusion associated HIV is frightening to many patients but actual risk is only 1 per 2 million products tested for HIV1 and about 1 per 5 million - 8 million products transfused in U.S.
- Pathogen inactivation has eliminated transmission in U.S. licensed plasma derivatives since 1985; however technique cannot be used for cellular components (Arch Pathol Lab Med 2007;131:719)
- Identification of recipients of products from HIV+ donors is mandated by FDA
- Risk in France is 1 per 3 million (Euro Surveill 2005;10:5); in Ivory Coast, the risk is 1 per 6,000 (Transfus Clin Biol 2006;13:242)
- Current standard is serologic antibody testing (1 per 33,000 positive) plus nucleic acid testing (reduces window of seronegativity between time of infection and development of antibodies, Transfus Med 2007;17:200)
- Risk exists for blood donated through window of seronegativity, and 4 "breakthrough" cases have been identified (nonreactive by nucleic acid testing - Vox Sang 2004;86:171, Transfusion 2004;44:929)
- Most transfusion medicine litigation focuses on transfusion acquired HIV (Arch Pathol Lab Med 2007;131:615)
HTLV
- HTLV is transmitted by vertical transmission from mother to child, breast feeding, sexual relations, parenteral exposure
- HTLV1 infects mostly CD4+ lymphocytes while HTLV2 infects preferentially CD8+ lymphocytes
- HIV was originally called HTLV-III but no longer; HTLV3 describes another virus
- In U.S., seroprevalence is 10 - 20 per 100,000 donors
Prevalence in donors:
- Brazil HIV clinic - 2% (Sex Transm Dis 2006;33:302)
- California (U.S.) - 1 per 900,000 (Transfusion 2006;46:703)
- India - 0.2% (Indian J Pathol Microbiol 2006;49:532)
- Peruvian pregnant women - 2% (J Acquir Immune Defic Syndr 2006;42:604)
- Saudi Arabia - < 0.01% (Saudi Med J 2004;25:1419)
- Senegal - 0.2% (J Clin Microbiol 2006;44:1550)
- HTLV1 is associated with adult T cell leukemia / lymphoma; endemic in Caribbean and parts of Africa, Japan, South America
- Transfusion of RBCs, platelets and whole blood but not FFP, have led to seroconversion of recipients
- In U.S., seroconversion rates are 14 - 30% in recipients of seropositive cellular components
- Risk of transfusion transmission is 1 per 3 million products transfused
- Most positive donors are asymptomatic
- HTLVI is rare in U.S.; HTLV2 is common in IV drug users in U.S.
- Donors in U.S. are tested for HTLV1 and 2
- Leukoreduction may be effective in removing HTLV (Transfusion 2004;44:42 but see Blood 2002;100:677)
West Nile virus
- West Nile virus is a flavivirus primarily transmitted through mosquitoes, with birds as immediate hosts (Wikipedia: West Nile fever [Accessed 31 October 2017])
- Entered North America in 1999; still epidemic in North America due to mosquito and bird vectors
- First appeared in New York in 1999 and rapidly expanded its geographical area within 3 years
- Symptoms: headache, new rash, generalized weakness (Transfusion 2006;46:272)
- May cause meningoencephalitis (Am J Clin Pathol 2003;119:749)
- Transfusion transmission resulted in 23 infections in 2002 during an outbreak
- Detected by nucleic acid based testing although virus adheres to human red blood cells in whole blood (Clin Infect Dis 2007;45:181)
- NAT testing was implemented in 2003
- Use of only minipool NAT testing resulted in 7 transfusion transmission cases in 2003 - 2004
Cost effectiveness models:
- In areas with high levels of transmission, seasonal screening of individual samples and restricting screening to blood donations designated for immunocompromised recipients is cost effective
- In areas with low levels of infection, using a standard questionnaire is cost effective (PLoS Med 2006;3:e21, PLoS Med 2006;3:e99; see also Ann Intern Med 2005;143:486 and Ann Intern Med 2005;143:537)
- In 2003 - 2005, 1,425 infected blood donors were identified in U.S. (Transfusion 2006;46:2038)
- In 2003, only 6 cases of transfusion transmitted WNV were documented in U.S. from 12.6 million blood units donated and 23 million blood transfusions; fewer since strategy changed from minipool to individual nucleic acid testing method in epidemic areas (Dev Biol [Basel] 2007;127:43, N Engl J Med 2005;353:460)
- Viral inactivation systems may be useful (Vox Sang 2006;91:345, Antiviral Res 2005;68:84)
- Donor prevalence rates: Mexico - 0.03% (Transfusion 2006;46:111), Netherlands - 0% (Vox Sang 2006;90:166)
- Epidemiologic reports from Centers for Disease Control (2002 - 2007): MMWR 2002;51:790, MMWR 2002;51:823, MMWR 2002;51:884, MMWR 2002;51:973, MMWR 2003;52:769, MMWR 2003;52:916, MMWR 2004;53:281, MMWR 2004;53:842, Emerg Infect Dis 2005;11:1167, MMWR 2007;56:76
