Transfusion-transmissible infections surveillance reports
In 2011, Lifeblood and the Kirby Institute published a comprehensive surveillance report for transfusion-transmissible infections (TTIs) - Safe blood – a focus on education, epidemiology and testing. This report analysed surveillance data for the period 2005–2010 and was the preface to planned annual TTI surveillance reports, with the first annual report being published the following year in 2012.
Lifeblood regularly reviews and updates the donor interview and selection process, taking into consideration local and overseas research studies, international best practice, literature reviews and analysis of surveillance data such as that included in this report.
The 2021 transfusion-transmissible infections in Australia surveillance report has now been published and the major findings and Lifeblood responses are as follows:
1. Supporting the effectiveness of donor education and selection, the prevalence of transfusion transmissible infections is substantially lower among first time blood donors (11-62 times) than in the general population in 2019, and with the exception of potentially infectious syphilis, shows a stable or declining trend over the period 2011-2020.The prevalence of active/potentially infectious syphilis in first time donors has been increasing steadily and now shows a statistically significant increasing trend for the 10 year period 2011-2020.
Lifeblood response to finding 1
While there is no directly comparable syphilis category to Lifeblood’s transfusion risk- specific active/potentially infectious syphilis category in the general population surveillance data, syphilis notifications including cases of infectious syphilis have been trending upward in both men and women. The notification rate of infectious syphilis among men has increased in the ten-year period, 2010-2019, from 9 per 100,000 in 2009 to 40 per 100,000 in 2019; similarly the rate among women has increased from 1 per 100,000 in 2010 to 8 per 100,000 in 2019.
2. The prevalence of transfusion-transmissible infections among first-time donations was much higher than the prevalence among all donations, highlighting the importance of promoting donor education of potential new donors and ensuring first-time donors read the pre-donation information and understand the importance of ‘self-deferral’.
Lifeblood response to finding 2 - Higher prevalence of transfusion-transmissible infections in first-time donors
Lifeblood focuses on education of all donors, particularly first- time donors, including providing a blood safety-based brochure translated into a number of languages highlighting the pivotal role of accuracy and honesty in answering the standard questionnaire.
In accordance with state and territory laws, there are penalties including fines and imprisonment for anyone providing false or misleading information.
While every effort is made to maximise donor retention, there is a fundamental requirement for continuing recruitment of new donors: firstly, to replace existing donors who can no longer donate (e.g. due to age and/or medical ineligibility) and secondly, to meet the growing demand for some blood products.
Lifeblood considers the current proportion of first-time donations (7% in 2020) to be acceptable, noting that this proportion is at the lower end of the range among internationally comparable blood services (7–25%). Importantly, achieving a lower proportion of first-time donors whilst maintaining fresh blood product sufficiency and expanding plasma donations is a positive outcome underpinned by an increasing annual average donation rate among repeat donors.
3. The incidence of newly acquired infection measured by the rate of incident donors is also much lower than results from specific at risk populations in Australia. This supports the general effectiveness of the donor questionnaire and specifically that repeat donors generally understand what constitutes ‘risk behaviour’ for acquiring transfusion transmissible infections.
4. Infective exposure risk factors identified in blood donors with transfusion transmissible infections closely parallel those for the general population with no ‘unique’ risk factors identified to date among blood donors.
5. The non compliance rate among TTI-positive donors in 2020 was 15%, at the lower end of the range of 13-25% observed in the last decade. The current rate highlights the importance of promoting donor education to ensure that the potential donors understand the importance of ‘self deferral’ to reduce the risk of collecting blood from a potentially infected donor whose infection may not be detected by testing.
6. While noncompliance among positive donors has been routinely monitored since 2000, the rate among TTI test-negative donors is more difficult to track.
Results from a large national survey conducted in 2012-2013 showed a comparatively low rate of reported non-compliance (in the range 0.05 to 0.29%) among TTI test-negative donors for several sexual activity-based donor deferrals. The study included a multivariate analysis of factors influencing non-compliance, which suggested that the use of a computer-assisted structured interview (CASI) might lead to further improvement in the overall compliance rate. Lifeblood has since fully implemented an electronic donor questionnaire (eDQ) at all blood collection sites.
Lifeblood response to findings 5 and 6 - Non-compliance to screening questions
Non-compliance to screening questions remains an ongoing concern despite existing donor education initiatives targeting the importance of complete accuracy and honesty in answering the donor questionnaire.
As noted, it is pleasing that the results of the national survey showed a comparatively low rate of non-compliance (in the range 0.05 to 0.29%) among TTI test-negative donors for several sexual activity-based donor deferrals.
While it is reassuring that Australian rates in 2012-13 were lower than comparable overseas rates, Lifeblood remains committed to seeking further improvement.
One potential strategy to improve compliance is optimising the communication of the rationale underpinning deferral policies. Lifeblood continues to engage externally regarding initiatives to improve communication. Recommendations include optimising the use of social media, developing new education resources and refining current education resources. One recent initiative was the translation into a number of languages of the ‘Safe blood starts with you’ brochure targeted at first-time donors. This is specifically aimed at improving understanding of blood safety concepts for prospective donors without English as a first language.
Furthermore, Lifeblood’s donor compliance study identified a correlation with non-compliance and concerns over ‘privacy’ of disclosure, which might be partially alleviated by the use of a ‘computer-based’ donor questionnaire. As noted in the response to Q6 above, Lifeblood has now fully implemented an electronic donor questionnaire at all collection sites. Post-implementation results indicate that this initiative has improved both the donor experience, as well as reducing procedural (‘human’) errors, thus enhancing overall system safety. Its impact on the non-compliance rate is unknown but is predicted to lead to a lower rate.
7. The estimated residual risk of transmission for HIV, HCV, HBV, HTLV and syphilis in Australia is very low – less than one in one million per unit transfused. This supports that Australia’s blood supply is among the safest worldwide in respect of transfusion transmissible infections for which testing is conducted. Despite this, there remains a minimal but real risk of transfusion transmissible infections that must be carefully considered before any transfusion.
8. Bacterial screening of 119,856 platelets identified 136 (0.11%) as confirmed positive. The majority of organisms identified were slow growing anaerobic skin flora not usually associated with post transfusion septic reactions. However, a minority of platelets grew clinically significant organisms that were likely to have been due to transient or occult bacteraemia in the donor and could have led to potentially serious septic transfusion reactions in the recipient. During 2020, there were no confirmed cases of transfusion transmitted bacterial infection. Based on Lifeblood data from May 2008 – June 2020, the risk of transfusion-transmitted bacterial infection from a platelet transfusion is calculated to be 0.47 per 100,000. This compares favourably with US data indicating a rate of 0.9 per 100,000 platelet units.
9. In addition to established transfusion-transmissible infections, emerging infectious diseases continue to demand vigilant surveillance and risk assessment. The ongoing risk from SARS CoV 2, local dengue outbreaks, seasonal West Nile virus outbreaks in Europe, outbreaks of hepatitis A virus and Zika virus was monitored during 2020- 2021. The risk to the blood supply posed by donors returning from Zika virus outbreak areas has been managed by deferring donation (or restricting to plasma for fractionation) for an appropriate period. Lifeblood continues to monitor hepatitis A virus, hepatitis E virus and Parvovirus B19 in Australia and a significant change in the risk profile has not occurred since the risk assessments were performed.
Lifeblood response to finding 9 - Surveillance for emerging infections
Lifeblood maintains surveillance for emerging infections through close liaison with government communicable disease control units, CSL Behring, membership of international medical/infectious disease groups and active horizon scanning.
Potential threats are regularly reviewed by Lifeblood Donor and Product Safety Committee and Clinical, Quality and Research Governance Committee, and risk assessment performed in the event that a threat is identified as a clear and present threat to the safety of the blood supply. Where appropriate, this will be performed in collaboration with CSL Behring (in their capacity as national plasma fractionator) and the Therapeutic Goods Administration.
Lifeblood has a comprehensive epidemic management plan - which was activated in response to SARS-CoV-2 (the novel virus causing COVID-19) in early 2020. Based on the epidemiology of known coronaviruses (SARS and MERS-CoV), the risk of transfusion transmission was assessed as low when the virus first emerged. The cumulative data, including over 250 million cases worldwide (at November , 2021) without a reported case of transfusion-transmission, supports that the risk is extremely low and currently ‘theoretical’.
The landscape for emerging infections that represent a potential risk to blood safety changed considerably in 2020 due to COVID-related travel restrictions significantly decreasing the risk. Notified case numbers for infections that have been predominately overseas-acquired, such as dengue, hepatitis and malaria, significantly decreased in 2020.