7.3.1. Hepatitis

Prospective blood donors should be given relevant information on the risk of hepatitis transmission in order to provide them with the opportunity to self-defer.

Prospective donors should be asked for a history of jaundice or hepatitis and whether they were further investigated to determine the cause. Individuals with a history of jaundice or hepatitis may, at the discretion of the physician, be accepted as donors based on the tests results.

To exclude donors at risk of transmitting hepatitis, the BTS should ask if the donor, currently or in the past, has had a hepatitis infection (HBV, HCV or other types), assess any specific risks of exposure through sexual and household contacts, and also enquire whether the donor has had an HBV vaccination within the last 14 days.

Individuals with hepatitis infection may be asymptomatic or present with fever, nausea, vomiting, loss of appetite, jaundice, abdominal pain or an enlarged and tender liver.

7.3.2. Human immunodeficiency virus/Acquired immunodeficiency syndrome (HIV/AIDS)

HIV can be transmitted via unprotected and close contact with a variety of body fluids of infected individuals, such as blood, breast milk, semen and vaginal secretions. Individuals cannot become infected through ordinary day-to-day contact such as kissing, hugging, shaking hands, or sharing personal objects, food or water.

Behaviours and conditions that put individuals at greater risk of contracting HIV include having unprotected anal or vaginal sex (186) (also refer to Section 7.9 on high-risk behaviours); having another sexually transmitted infection such as syphilis, herpes, chlamydia, gonorrhoea or bacterial vaginosis; sharing contaminated needles, syringes and other infected equipment and drug solutions for injecting drug use; receiving unsafe injections, blood transfusions or medical procedures that involve unsterile cutting or piercing; experiencing accidental needlestick injuries, including among health workers.

Infectivity estimates in case of transfusion of infected blood products are much higher (around 95%) than for other modes of HIV transmission owing to the much larger viral load per exposure than for other routes (187)

7.3.3. HTLV I and HTLV II

Human T-cell lymphotropic viruses (HTLV) are present in the bloodstream in lymphocytes. Non cell-associated virus is rarely found. The infectivity of blood and blood components is reduced but not removed by leucodepletion. HTLV can be transmitted from mother to child, primarily through breast-feeding, and it may also be transmitted through sexual contact (188,189). As infection is considered to persist for life, screening for anti-HTLV identifies donations that may transmit HTLV but does not in itself indicate the timescale of an infection.

7.3.4. Herpes viruses

Herpes viruses include herpes simplex types I and II, varicella-zoster, Epstein-Barr virus, cytomegalovirus and Kaposi's sarcoma-associated human herpes virus 8 (HHV8). All these viruses can give rise to latent infection and some are transfusion-transmissible (190,191). Symptomatic donors should be deferred until fully recovered. Because of the high prevalence of exposure to these viruses in donors and recipients, except in the case of HHV8, the exclusion of donors with a history of past infection is neither feasible nor useful.

HHV8 is transmitted by sexual and non-sexual routes and has been reported to be also transmitted by transfusion and transplantation (192,193,194).

7.3.5. Mosquito-borne viruses

7.3.6. “Childhood illnesses”: measles, rubella, mumps and chickenpox

Infections with childhood illnesses such as measles, rubella, mumps and chickenpox are known to occur in adults. Individuals suffering from any of these childhood illnesses and their close contacts should be identified as ‘at-risk’ donors and should be deferred for a defined period of time (205,206).

7.3.7. Influenza

For sporadic cases, individuals with active infection should be deferred until 14 days after full recovery; susceptible contacts should be deferred for 7 days after the implicated individual has recovered.

In a pandemic situation the risk of blood shortage far outweighs any theoretical risk of transfusion transmission. The usual donor selection criteria for influenza and any specific measures relating to donor deferral should be carefully reviewed. Following the precautionary principle, selective donor deferral may be considered (25,207).

7.4.1. Malaria

Malaria is caused by Plasmodium species. There are four parasite species that cause malaria in humans: P. falciparum, P. vivax, P. malariae and P. ovale, of which P. falciparum and P. vivax are the most common. P. falciparum is the most deadly. In recent years, some human cases of malaria have also occurred with P. knowlesi – a species that causes malaria among monkeys and occurs in certain forested areas of South-East Asia.

Malaria is primarily transmitted to humans through the bite of the female Anopheles mosquito. In many places, transmission is seasonal, with the peak during and just after the rainy season. Increased malaria prevention and control measures are dramatically reducing the malaria burden in many places. Nonimmune travellers from malaria-free areas are very vulnerable to the disease when they become infected (208).

Malaria is also readily transmitted by blood transfusion through donations collected from asymptomatic, parasitaemic donors. The parasite is released into the bloodstream during its lifecycle and will therefore be present in blood donated by infected individuals. The parasites are stable in plasma and whole blood for at least 18 days when stored at +4°C and for extended periods in a frozen state (209). Donor selection criteria to exclude collecting blood from individuals with current or past history of malarial infection and at risk of transmitting malaria through transfusion, should be based on local epidemiological evidence and endemicity of the infection.

7.4.2. Chagas disease

Chagas disease, also known as American trypanosomiasis, is a potentially life-threatening illness caused by the protozoan parasite, Trypanosoma cruzi (T. cruzi). It is found mainly in Latin America, where it is mostly transmitted to humans by the faeces of triatomine bugs, known as “kissing bugs”, among other names, depending on the geographical area. T. cruzi can also be transmitted by food contaminated with T. cruzi through for example the contact with triatomine bug faeces, transfusion of blood from infected donors, passage from an infected mother to her newborn during pregnancy or childbirth, organ transplants using organs from infected donors and laboratory accidents.

Chagas disease is endemic throughout South and Central America, although effective vector control procedures have been implemented in recent years (213,214,215,216). In the past decades, it has also been increasingly detected in the United States of America, Canada, many European and some Western Pacific countries. This is due mainly to population mobility between Latin America and the rest of the world. Less frequently, it is due to infection through blood transfusion, vertical transmission (from infected mother to child) or organ donation (217).

Infection is life long and infected individuals may be asymptomatic; individuals with a history of T. cruzi infection should be permanently deferred.

7.4.3. Babesiosis

Babesiosis (Babesia sp.) is transmitted by tick-borne intraerythrocytic parasites. Most cases of Babesia infection are asymptomatic, but can include mild fever and diarrhoea. The symptoms are often unnoticed or unexplained. In more severe cases, the symptoms are similar to those of malaria. The infection may also have a chronic asymptomatic phase and the parasite can survive blood storage conditions. B. microti is endemic in parts of North America; the reservoir of infection is small rodents. Transfusion-transmission has been reported (222,223). Prevention relies on checking for a history of previous infection among residents or visitors to endemic areas (224,225,226).

7.4.4. Leishmaniasis

Leishmaniasis is a parasitic disease endemic in the tropics and subtropics, transmitted by the bite of infected sand-flies. The parasite (Leishmania sp.) has the potential for transfusion-transmission, but this has been only rarely reported, possibly because parasitaemia is transient and low level (227). The prevention of transfusion-transmission relies on the permanent deferral of infected individuals (228).

7.5.1. Syphilis, yaws and gonorrhoea

Syphilis, yaws and gonorrhoea are common sexually-transmitted diseases; it should be noted that a history of sexually transmitted disease is an important indicator for sexual behaviours associated with HIV transmission. Controlling sexually transmitted infections is important for preventing HIV infection, particularly in people with high risk sexual behaviours (232).

The risk of transmission of syphilis (T. pallidum) through the transfusion of processed and stored blood is low as the spirochaetae are released into the bloodstream only intermittently during the course of infection, and are destroyed within 72 hours of storage at +40°C (63); however T. pallidum can be transmitted through fresh blood and platelets. It is not transmitted by plasma products fractionated from pooled plasma such as Factor VIII.

Yaws (Treponema pallidum pertenue) is not transmitted through transfusion, but is serologically indistinguishable from syphilis. Serological tests for syphilis may remain positive for many years after successful treatment.

The causative agent of gonorrhoea (Neisseria gonorrhoeae) is not transmissible by blood transfusion. Nevertheless most BTS defer individuals with gonorrhoea for 12 months following completion of treatment.

7.5.2. Lyme disease

The spirochete Borrelia burgdorferi is carried by insect vectors including ticks, horseflies and mosquitoes. It can survive blood storage temperatures. Transfusion-transmission is possible but has not been reported. Infected individuals usually exhibit symptoms of rash, fever, lymphadenopathy, often progressing to chronic arthropathy and/or neurological involvement, and are likely to be Identified and excluded by careful donor selection (222).

7.5.3. Brucellosis

Brucellosis (undulant fever) is caused by the bacterium Brucella melitensis. It is usually acquired from an infected animal source but is not usually transmitted from person to person. Transfusion-transmission has been reported in endemic regions. Infection is usually chronic; this may last for many years with bouts of sometimes quite serious illness.

7.5.4. Yersinia infection

This gram-negative bacterium (Yersinia enterocolitica) causes enteritis and is of particular concern as it can multiply at +4°C; thus a low-grade bacteraemia in a donor is capable of causing severe, sometimes fatal post-transfusion sepsis and toxic shock in the recipient. The incidence of this complication has been estimated at 1:6 million red cell transfusions (233).

Donors should be asked about any recent abdominal symptoms, particularly diarrhoea, and deferred if they have a history suggestive of Y. enterocolitica. They should be asked to inform the BTS if they develop such symptoms within 14 days of donation. As symptoms may be absent or non-specific, potentially infected donors cannot reliably be Identified.

7.5.5. Salmonella, campylobacter, streptococcus and staphylococcus

Post-transfusion sepsis may result from donor bacteraemia associated with gastrointestinal, urinary or wound infections (also refer to Section 4.3 on minor illnesses).

7.5.6. Tuberculosis

There is no published report of transfusion-transmission of tuberculosis (Mycobacterium tuberculosis) even though the organism is blood-borne.

7.7.1. Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease (CJD) is the human form of transmissible spongiform encephalopathy. It exists in four distinct forms: sporadic, genetic (familial), iatrogenic and variant (vCJD).

There is no evidence of transfusion-transmission of sporadic and familial CJD; nevertheless, donors with symptoms suggestive of CJD or a family history of CJD should be permanently deferred (235). Iatrogenic CJD has been described following treatment with pituitary-derived human growth hormone, human gonadotrophin, dura mater grafts, corneal transplants and through contaminated neurosurgical instruments. There is no evidence of transfusion-transmission of iatrogenic CJD; however donors with a history of such interventions should be permanently deferred (236).

7.7.2. Variant Creutzfeldt-Jakob disease

Variant Creutzfeldt-Jakob disease (vCJD) emerged in the United Kingdom of Great Britain and Northern Ireland (UK) in 1996 as a result of oral transmission of spongiform encephalopathy from infected cattle. Data on the number of cases worldwide are collected and published by the UK National Creutzfeldt-Jakob Disease Research & Surveillance Unit (237). The outbreak of cases in the UK has declined but a “second wave” cannot be excluded and cases have occurred in other European Union countries (70)

Epidemiological evidence from the UK indicates that vCJD can be transmitted by blood transfusion, with important implications for public health worldwide (238,239,240,241). WHO guidelines on tissue infectivity distribution in transmissible spongiform encephalopathies (242) recommend that national authorities should prepare plans for measures to minimize the risk of transfusion-transmission of vCJD by blood and blood products, whilst not compromising the adequacy of the blood supply, and provide guidance on risk assessment.

To date, many countries have addressed this risk by excluding blood donors with a history of travel or residence in the UK and parts of Europe, for defined cumulative exposure periods. The United States Food and Drug Administration currently requires deferral of individuals who have spent 3 months or more cumulatively in the UK between 1980 and the end of 1996, when effective measures were implemented to prevent oral transmission, or who have spent 5 years or more cumulatively in Europe between 1980 and the present (236). In the UK, France and Ireland, recipients of blood transfusion (including fractionated blood products) since 1980 are now permanently deferred. Other countries defer donors who have received blood transfusions in the UK or France since 1980.

7.9.1. High-risk sexual behaviours

Certain sexual behaviours have been shown by surveillance data to be associated with a high risk of transmission of HIV, HBV and HCV (246,247). It is essential that BTS identify and defer from blood donation individuals whose sexual behaviour puts them at high risk of acquiring infectious diseases that can be transmitted through blood. Deferral policies for high-risk behaviours should be supported by public education. Deferral criteria should be simple and easily understood by staff and prospective donors and should ideally enable self-deferral, without the need for detailed intrusive questioning about an individual's sexual behaviour (248,249); they should be applied with sensitivity, a non-judgemental approach and assurance of confidentiality.

High-risk sexual behaviours include having multiple sex partners, receiving or paying money or drugs for sex, including sex workers and their clients, men having sex with men (MSM) (250,251) and females having sex with MSM (246,247,252). MSM account for the largest subpopulation of HIV-infected people in most developed countries (253,254,255,256) and many countries therefore permanently defer men who have ever had oral or anal sex with another man (254,257,258).

The permanent deferral of MSM has been criticized as being selectively discriminatory and lacking scientific rigour (253,259,260,261) and has undergone review in some countries in the light of increasingly sensitive and reliable technologies for donation screening (249,262). Studies using mathematical modelling to predict the effect of reducing deferral intervals for MSM to one or five years have suggested that the increased risk of an HIV-infected donation entering the blood supply is small, but not zero, with little gain in terms of additional donations (263,264,265,266). These studies rely on some assumptions, are applicable only to the populations studied, and relate to testing methodologies that are not available in some countries and have been superseded in others. However, no comparable evidence is currently available. The permanent deferral of MSM therefore continues to be endorsed as the default position based on the principle of risk reduction to “as low as reasonably achievable” (ALARA).

Deferral criteria for high-risk sexual behaviours in a particular country or region should be determined and reviewed frequently, based on the residual risk of transfusion-transmitted viral infections, taking into account changes in disease epidemiology, improvements in available technologies for donation testing and on-going research.

7.9.2. Injecting drug use

The use of injected “recreational” drugs and non-prescribed steroids is commonly associated with unsafe practices such as the sharing and re-use of needles. It carries a high risk of blood-borne infections, most commonly HCV, but also HBV and HIV (246,267,268,269,270,271,272,273,274).

Many injected drugs are highly addictive and their use may be life-long. The safest policy is therefore permanent deferral of anyone who has ever injected non-prescribed drugs. Deferral policies should be regularly reviewed as new evidence emerges.

7.9.3. Non-injected drugs and alcohol use

The use of alcohol and non-injected “recreational” drugs is widespread in most cultures, and many local practices exist.

Prospective donors who demonstrate signs and symptoms of intoxication should be deferred as their capacity to give informed consent is likely to be impaired. A further consideration is whether regular heavy drinking or use of illicit drugs and other dependence-producing psychoactive substances is a marker for other high-risk behaviours.

The use of intranasal cocaine has been found to be a risk factor for HCV (275).

There is no documented evidence that recent ingestion of a “recreational” drug (e.g. kava) or alcohol by a donor has caused harm to the recipient of their blood. As is the case for prescribed medication, the dilution factor is such that the blood recipient receives a very small residual quantity, which is unlikely to have any adverse effect.

Considerations regarding possible allergic reactions to non-prescribed drugs in recipients are the same as for prescribed medications (also refer to Section 6.2 on medications).

7.9.4. Detention in prisons and penal institutions

Inmates of prisons and penal institutions should not be accepted as blood donors as there is evidence of a higher incidence of HIV, HBV and HCV in these populations (276,277). In addition, there is a risk that there may be undue coercion to donate blood in these settings and that the donation may not be voluntary. The acceptance of individuals with a history of previous imprisonment requires assessment of their exposure to risk from drug use, injuries or unsafe sexual practices with the consequent appropriate deferral period.

7.9.5. Cosmetic treatments and rituals

Any procedures involving penetration of the skin carry a risk of bloodborne infections, especially HIV, HBV and HCV, unless performed under sterile conditions. These include body piercing, tattooing, scarification, injections with collagen or botulinum toxoid (botox), electrolysis and semi-permanent make-up (267,268,270,271,278,279,280,281,282).

Individuals who present with a history of any procedures involving penetration of the skin should be assessed for the risk of TTI, based on when, where, by whom and how the procedure was performed. The BTS should define the deferral period, based on the sterility and safety of the procedure. If it is not possible to ascertain the sterility and safety of the procedure, the individual should be deferred for a period of 12 months.