Hepatitis E virus risk management strategy: a large scale study of blood donations

What was the question?

We wanted to find out whether any of our blood donors were infected with the hepatitis E virus (HEV).
This information will be used to assess the risk of transmitting HEV through blood transfusion, and help
us decide whether we need additional controls to keep
the blood supply safe.

Why is it important?

HEV can cause water-borne hepatitis outbreaks in developing countries. In developed countries, HEV can
be transmitted by eating undercooked contaminated meat, particularly pork and pork products. The majority of HEV infections reported in Australia are acquired overseas.1 Infection can result in symptoms such as vomiting, diarrhea, jaundice and liver swelling, however, not all infected individuals develop symptoms, and in developed countries the majority of infected individuals
don’t show any symptoms.

The virus can be present in a person’s blood before they show symptoms, so transmission through blood transfusion is possible, and has been demonstrated several times overseas. The Lifeblood doesn’t routinely test for HEV because, although common worldwide, it is not thought to be generally acquired in Australia. But, as HEV is an emerging issue for all Lifeblood, we decided to investigate how prevalent it is to make sure we’re doing everything we can to ensure our blood supply remains safe.

What did we do?

We collected an extra plasma sample from 74,131 blood donors nationally between May and November, 2016. We tested for the virus in the donor blood samples by looking for its genetic material (RNA).

What did we find out?

We detected one HEV RNA positive donation in 74,131 blood donations. This prevalence in Australian donors is estimated as one in 74,131 (95% CI, 1 in 420,168 to 1 in 13,087), lower than other developed countries such as the UK, Germany and USA. The viral load in the donation (180 IU/mL) was below the minimum viral load demonstrated to result in transfusion-transmission.2 Our results show that the risk of collecting
a HEV infected  blood donation in Australia is low, and much lower than the risk in other developed countries, where selective screening has been implemented. We will use this prevalence to update our original HEV Blood Safety Risk Assessment. Whilst a final decision is dependent on the risk assessment and in particular assessing the risk in vulnerable recipient groups, the very low prevalence found suggests universal HEV blood donation screening in Australia is not currently needed.

This work is currently being written up for publication. If you would like more information, please contact Dr Helen Faddy (hfaddy@redcrossblood.org.au) or Dr Veronica Hoad (vhoad@redcrossblood.org.au).

We would like to thank the donor centre staff and donors in all centres involved and also Manufacturing staff for assistance with this study. The study would not have
been possible without you.

References

1. Shrestha AC, Flower RLP, Seed CR, et al., Hepatitis E virus infections in travellers: assessing the threat to the Australian blood supply. Blood Transfus. 2016 Jul 22:1-8. doi: 10.2450/2016.0064-16.
2. Hewitt PE, Ijaz S, Brilsford SR, et al., Hepatitis E virus in blood components: a prevalence and transmission study in southeast England. Lancet. 2014 Nov 15;384(9956):1766-73. doi: 10.1016/S0140-6736(14)61034-5 RESEARCH STUDY UPDATE: Hepatitis E virus risk management strategy: a large scale study of blood donations