WHO/EHT/11.03 Maintaining a Safe and Adequate Blood Supply during Pandemic Influenza Guidelines for Blood Transfusion Services July 2011 1
1 Introduction During the 2009 influenza pandemic, over 600 000 confirmed cases of pandemic influenza (H1N1) worldwide were reported (1), affecting more than 208 countries (2). The status of the H1N1 (2009) virus was changed to post‐pandemic in August 2010 but, based on knowledge about past pandemics, the virus is expected to continue to circulate as a seasonal virus for some years to come (3). While the level of concern is now greatly diminished, vigilance and continuing surveillance by national health authorities remains important (4). Transfusion support is an essential component of clinical medicine, being life‐saving in many acute situations and with many chronically‐ill individuals receiving regular transfusion therapy. Maintaining a safe, sufficient and accessible blood supply in the face of widespread disease is essential. It is therefore critical that blood transfusion services (BTS) recognize the potential impact of pandemic influenza on blood supply systems and put contingency plans in place to ensure the maintenance of core services in the face of such a pandemic. Influenza viruses are airborne and spread through direct contact with an infected individual. There is currently no evidence of the transmission of influenza through transfusion; however, viraemia may occur (5) with the (remote) possibility of a blood donation being collected from an otherwise well individual who may present to donate but may be viraemic. While influenza has been the cause of the most recent pandemic, there are other infections whose spread may also result in a pandemic situation. Although this particular document is specific to pandemic influenza, each BTS should put plans into place to be able to identify and respond to any pandemic situation. The guidelines have been developed by the World Health Organization Blood Transfusion Safety programme. They focus on the collection, processing and transfusion of blood and blood products. The same basic principles can also be applied to the collection, processing and use of other banked products such as tissues and stem cells. However, the nature of a number of tissue products is such that the risk of transmission may be different from that of blood and blood products and specific individual risk assessments should be undertaken for the different tissue types and storage conditions. These guidelines will be reviewed and updated as new information becomes available. They are compiled to provide a generic basis on which national health authorities may wish to use in developing guidelines applicable to their own particular circumstances. 2 Recommendations The WHO Blood Transfusion Safety programme proposes the following precautionary principles to blood transfusion services to ensure the safety and adequacy of national blood supplies in the face of pandemic influenza. 1 Ensure the inclusion of the national BTS in the national pandemic influenza contingency planning body. 2 Establish a mechanism for the BTS to receive regular, up‐to‐date epidemiological information on the spread of pandemic influenza and other outbreaks in the country. 2
3 Develop a contingency plan, which is reviewed constantly, to enable the BTS to continue to meet national requirements for blood and blood products, considering:  Risk of transmission of influenza by blood transfusion  Temporary loss of blood donors resulting in a reduced supply of blood donations  Effects of an influenza vaccination programme on the suitability of prospective donors to donate blood  Temporary loss of staff working in blood transfusion services  Changes in clinical demands for blood and blood products. 4 Work with national health authorities, hospitals and other responsible bodies to predict expected blood usage during the pandemic and plan BTS activities flexibly to meet actual requirements as far as possible. 5 Provide advice and guidance to prospective donors on their eligibility to donate following vaccination against pandemic influenza or exposure to infection. 6 Provide advice, guidance and, where appropriate prophylaxis, to all staff to minimize the risk of infection and the spread of infection, in accordance with any specific requirements in the national pandemic influenza contingency plan. 7 Work with identified key suppliers of critical consumables, including blood collection bags, test kits and reagents, to minimize the risk of supply chain failures as a constraint on maintaining a safe blood supply. 3 General considerations While national planning focuses particularly on the early detection, verification and containment of infection, the implications for other aspects of health care of the rapid spread of an acute and severe infectious disease must be considered; blood transfusion support is such an example. To maximize the effectiveness of its response to pandemic influenza, the BTS should ensure that it is actively involved in the national contingency planning body for pandemic influenza. This will help to ensure that the BTS is informed as early as possible about the emergence of infection and the subsequent intended actions, including planned vaccination programmes. This information can then be used in the BTS’s own contingency planning to maintain continuity in the supply of blood and blood products and respond to possible changes in the demand for these. The BTS can plan effective responses only if this information is available to it as early as possible. The BTS organizational contingency plan should address issues related to blood donation, the possible cancellation and replacement of blood donation sessions in areas in which cases have been identified and any potential changes in local or national requirements for blood and blood products. In addition, in situations where containment measures are likely, or already in place, the BTS should ensure that its activities do not compromise containment efforts. A major factor in the ability of a BTS to maintain a safe and adequate blood supply is its organizational structure and the number of:  Blood donation sites and sessions  Blood collection teams  Blood donors or potential donors within the catchment area of each donation site or session. 3
In countries with isolated population groups, for example, it may be possible to focus collection activities in areas where a pandemic infection might take longer to infiltrate. Increased activities at these donation sites may cover potential losses at sites closer to or in areas in which pandemic infection is already present or more likely to occur. The use of public media to educate, inform and motivate blood donors may also help in such situations. However, widespread infection should be anticipated and, in denser or more mobile populations, measures to move blood supply activities from one area to another should not be relied on as an effective measure. For this reason, and because the impact of pandemic influenza on the demands for blood and blood products is extremely difficult to quantify in advance, the BTS should also aim to have plans in place that can focus potentially severely limited resources on meeting the most acute clinical needs for transfusion support. Additional safety measures for the health and protection of staff and blood donors will need to be considered and introduced as appropriate and in compliance with local public health guidance. The BTS should identify the critical consumable items and essential equipment on which it depends. Greater resilience in the supply chain may be achieved by such measures as working with suppliers in advance, ensuring that equipment is regularly serviced or setting revised stock holding levels for key consumable items. 4 Risk of transmission through blood transfusion The risk of the direct transmission of influenza through blood or blood products is believed to be extremely low. There are no published reports of the transmission of any influenza viruses by blood transfusion in humans or in animal models. The transmission of a respiratory virus by transfusion is very unlikely to result in an infection in the transfused patient although, in the most extreme cases where the blood donor is viraemic with a particularly high viral load (5), the possibility of transmission has to be considered; in these circumstances, however, the donor is unlikely to be well enough to donate. Therefore, while it is not possible definitively to rule out any theoretical risk of the transmission of influenza through blood transfusion, in practice the risk of this occurring is very small. However, further research is required to assess the level of viraemia in asymptomatic patients and the consequent risk of transmission through transfusion. It will be of particular importance to assess the clinical characteristics of pandemic strains, including transmissibility, via the bloodborne route. The early symptoms of influenza are very similar to those of most other respiratory viruses. National blood donor selection guidelines should specify that a prospective donor who is symptomatic should not be accepted to donate blood further stating the recommended deferral period for deferred donors. Importantly, a major assumption in all current international contingency planning for pandemic influenza has been that infection with the pandemic virus leads to moderate to severe respiratory illness. The incubation period for human influenza viruses in general is short, commonly 2 to 4 days (range 1 to 7 days). However, with influenza A (H1N1), the median time between exposure and the onset of illness is 3 days (range 2 to 4 days). Understanding the timings of infection is important in the donor selection process as the shorter the period of time between exposure and onset of illness, the less likely it is that an asymptomatic infected individual would present to donate. 4
5 Temporary loss of blood donors and the impact on the blood supply As infection spreads through a population, there will be a decrease in the number of potential blood donors available at any one time. This is due to infection in donors, their families and contacts, restrictions on movement, including blood collection activities in areas in which outbreaks have been recorded, and the unwillingness of some individuals to donate through fear of being infected by being in close contact with others. In addition, where vaccination programmes to protect against pandemic influenza are implemented, there may be a temporary loss of donors following vaccination, depending on the groups targeted for vaccination. Infection in blood donors Infection in the general population will result in a decrease in the number of blood donors available. Using current infection rates and cases per 100 000 population, an estimate can be calculated of the number of potential donors who could be lost due to infection. If the current infection rate is 1000 cases per 100 000 population and an infected individual is symptomatic for 7–10 days (6), it can be considered that over the course of a pandemic each week approximately 1–2% of donors would be unable to donate due to infection. These individuals should be actively encouraged to donate two weeks after full recovery and cessation of therapy. It is critical that blood collection activities continue, but on a more targeted basis through the identification, recall and recruitment of healthy donors with the aim of maintaining blood collections at the required level to continue to meet demand. The BTS must also ensure the safety of the donation process through the use of protective measures by staff, such as hand hygiene and the use of masks that are consistent with local public health guidance. Infection in families or contacts of blood donors Donor numbers may decrease due to infections among donors’ families and contacts rather than among donors themselves, often because of the time requirements in caring for infected individuals. In such a situation, donors would be unsuitable to donate as they would have been exposed to known infected individuals and might be at an early stage of infection themselves. The losses of donors in this category may be higher than in those actually infected. Although hard to quantify, weekly losses of up to 10% may occur, depending on household sizes and contact levels. Vaccination against pandemic influenza Many countries have introduced vaccination programmes to help protect individuals against pandemic influenza. These programmes initially target the highest‐risk individuals and may include a subsequent roll‐out to the general adult population. Consequent upon this, there is the need to consider whether a prospective donor who is recently vaccinated should be deferred for an appropriate time following vaccination. Specific guidance should be added to existing donor selection guidelines to cover the management of donors who have been vaccinated against the H1N1 virus. There is currently no evidence that a donation collected from a recently vaccinated donor would present any risk to transfused patients. However, in order to ensure donor health and safety, prospective donors should be deferred for 48 hours after vaccination because of potential side‐effects to the vaccine. It is also important to ensure that any other risks in such donors which may require a longer deferral (i.e. specific reasons for vaccination), are not overlooked. 5
Blood donor selection Usual donor selection criteria and any specific measures relating to donor deferral should be carefully reviewed during pandemic influenza. Following the precautionary principles, WHO recommends selective donor deferral, as follows: Asymptomatic, no close contact* Suitable to donate Asymptomatic, with close contact* Defer for one week after last day of close contact Symptomatic (confirmed or probable case) Defer for two weeks after full recovery and cessation of any therapy Vaccination Defer for 48 hours after vaccination; the deferral period should be increased as above if the donor is in a specific risk category * Close contact: having cared for, lived with, or had direct contact with the respiratory secretions or body fluids of an individual with a suspected or probable case of H1N1 influenza A major question to consider is whether criteria for assessing the suitability of individuals to donate blood should be relaxed in order to avoid blood shortages resulting from a reduced number of healthy donors. In general, no changes should be permitted to criteria for temporary or permanent deferral in order to protect the health of donors. Raising the upper age limit for donors, preferably regular donors, or lowering minimum haemoglobin levels may be considered as a last resort (6). Such changes should be permitted only in situations of extreme blood shortage and under the responsibility of a suitably qualified professional. The decision points for relaxing donor selection criteria should be determined by the national health authority in each country. No changes should be permitted to the mandatory national requirements for the screening of donated blood for transfusion‐transmissible infections. Restrictions on blood collection activities As cases of influenza occur, various strategies may be implemented in the attempt to minimize the spread of infection and its effects on the population. Pandemic influenza preparedness and response: a WHO guidance document (7) outlines specific responses required to help mitigate the impact of a global pandemic. These include planning and coordination, monitoring and assessment and strategies to help reduce the spread of the infection globally, nationally, regionally, locally and to the level of the individual. The document suggests a number of approaches including vaccination, restriction of social interaction by infected individuals with non‐infected individuals and restrictions on movements into and out of areas in which infections have been confirmed. The containment strategy may impact directly on blood collection activities by limiting the ability of donors to attend donation sessions and, more importantly, by preventing mobile blood collection teams from visiting certain venues or areas. In addition, blood collections may need to be limited significantly at certain times and in certain areas to prevent staff from being exposed unnecessarily to infection or contributing to the spread of infection. Contingency planning for this is essential. Alternative strategies are needed to enable the rapid switching of blood collections from area to area, where this is feasible, avoiding high infection areas and concentrating on educating and motivating donors and potential donors in low‐risk areas. 6
Public and blood donor awareness Ignorance, misinformation or fear of exposure to an increased risk of infection may deter individuals unnecessarily from donating blood. Effective public awareness campaigns on the importance of maintaining an adequate national blood supply, the need for blood donors and the safety of the donation process should therefore be disseminated continuously throughout the pandemic, using all available media. The BTS should also inform donors and the general public about influenza, routes of transmission and signs and symptoms of infection in accordance with the national campaign strategy. Specifically, donors and potential donors should be informed of the importance of:  Self‐deferral from blood donation if feeling unwell  Reporting immediately to the BTS any illness within a specified time following donation  Resuming blood donation after an appropriate time following complete recovery. 6 Temporary loss of staff working in blood transfusion services As infection spreads, in the absence of any specific preventive interventions BTS staff will be at equal risk of acquiring infection as the rest of the population. While the spread of infection within the community cannot be prevented, its transmission within the workplace can be more easily controlled if staff are properly educated and advised in advance not to attend work if they feel ill and may have been infected. In addition, WHO recommends that health workers be given first priority for early vaccination to protect themselves and their patients and to help keep health systems functioning as the pandemic evolves (8). The vaccination of BTS staff, if available, should be considered a core strategy to minimize the impact of pandemic influenza on staff availability. The loss of staff at any one time is hard to predict but, in severe cases, staffing levels may fall by 50%, although a peak loss of around 30–35% is considered more likely. The temporary unavailability of staff is highly likely to affect BTS activities directly and indirectly, such that the blood and blood products available for transfusion may be limited. Depending on the organization and structure of the BTS, activities could be reorganized from site to site as the pandemic moves across the country and as staff become ill, then recover and return to work. However, in smaller, more densely populated countries or those with more mobile populations, such measures are less likely to be of benefit. In these circumstances, a more effective approach will be to carefully target limited staff resources on the most essential activities to maintain life‐saving transfusion services. 7 Changes in the clinical demand for blood and blood products National health authorities are responsible for contingency planning in advance of a pandemic and for prioritizing limited health‐care resources. Planned or forecast changes in clinical requirements for blood and blood products should be quantified, if possible, and addressed in contingency plans, specifically to feed into planned changes in blood collection activities. Blood stock management and movement should ensure availability of blood where ever it may be needed despite the low stocks resulting from the pandemic. During a pandemic phase, a reduction in the demand for blood and blood products may result from specific contingency planning involving the overall re‐provisioning of health care and the cessation of all elective surgery and other non‐urgent interventions that may require blood or blood products and reserving available stocks for dire emergencies in collaboration with hospitals and clinicians. Planned reductions of 20–50% in blood usage can often be achieved in situations where at least a 7
certain amount of blood is used in routine, planned, but non‐emergency situations which can be forecast with some degree of accuracy. In situations where the blood supply is already limited and where most blood is used in acute/emergency situations (e.g. childbirth, severe infant anaemia due to malaria, trauma), planned reductions are not possible and no more than a 10% fall in demand can be anticipated. The demand may be reduced in situations where restrictions on the movement of individuals and social interaction are implemented, but this is likely to be minimal. The demand for blood and blood products may decrease as infection spreads to health‐care staff and they are unable to work, affecting the ability of hospitals to function. However, if there is a vaccination programme that targets health‐care staff, health‐care provision may not need to be reduced significantly as a result of staff shortages. Nevertheless, the BTS contingency plan should aim to avoid restricting blood supplies any more than is absolutely necessary in order to avoid creating an additional burden on or risk to already stretched health‐care services. The BTS may need to follow actual falls in demand for blood and blood products rather than to predict and meet those predicted reduced levels of demand. It is therefore essential that the BTS is fully integrated into the country’s pandemic influenza planning system to ensure that blood requirements are understood and can be met. 8 References 1 Pandemic (H1N1) 2009. Update 76, 27 November 2009. Geneva, World Health Organization, 2009. www.who.int/csr/don/2009_11_27a/en/index.html 2 Pandemic (H1N1) 2009. Update 81, 30 December 2009. Geneva, World Health Organization, 2009. www.who.int/csr/don/2009_12_30/en/index.html 3 WHO recommendations for the post‐pandemic period. Pandemic (H1N1) 2009 briefing note 23. Geneva, World Health Organization, 2010. www.who.int/csr/disease/swineflu/notes/briefing_20100810/en/index.html 4 Surveillance recommendations for Member States in the post‐pandemic period, 12 August 2010. Geneva, World Health Organization, 2010. www.who.int/csr/resources/publications/swineflu/surveillance_post_pandemic.pdf 5 Arbeitskreis Blut. Influenza virus. Transfusion Medicine and Hemotherapy, 2009, 36(1):32 39. 6 Donor selection in case of pandemic situations. Geneva, WHO Blood Regulators Network, 2007. www.who.int/bloodproducts/brn/DonorSelectionincaseofPandemicSituations.pdf 7 Global Influenza Programme. Pandemic influenza preparedness and response. A WHO guidance document. Geneva, World Health Organization, 2009. www.who.int/csr/disease/influenza/PIPGuidance09.pdf 8 WHO recommendations on pandemic (H1N1) 2009 vaccines. Pandemic (H1N1) 2009 briefing note 2. 13 July 2009. Geneva, World Health Organization, 2009. www.who.int/csr/disease/swineflu/notes/h1n1_vaccine_20090713/en/index.html 9 Bibliography 1 2 3 4 5 Pandemic (H1N1) 2009. Geneva, World Health Organization, 2009. www.who.int/csr/disease/swineflu/en/ Pandemic (H1N1) 2009. London, Health Protection Agency. www.hpa.org.uk/HPA/Topics/InfectiousDiseases/InfectionsAZ/1240812234677/ Recommendations for the assessment of blood donor suitability, blood product safety and preservation of the blood supply in response to pandemic (H1N1) 2009 virus. Maryland, U. S. Food and Drug Administration, 2009. www.fda.gov/downloads/BiologicsBloodVaccines/GuidanceComplianceRegulatoryInformation/Guidan
ces/Blood/UCM190373.pdf Information about newly emerging 2009 H1N1 influenza virus and blood safety. Maryland, Food and Drug Administration, 2009. www.fda.gov/BiologicsBloodVaccines/SafetyAvailability/VaccineSafety/ucm161918.htm 2009 H1N1 flu. Atlanta, Centers for Disease Control and Prevention, 2009. www.cdc.gov/H1N1FLU/ 8