Blood donations are safe during the pandemic and do not carry a risk of COVID-19 infection risk, a new study suggests.
Earlier in the crisis, scientists worried that blood donors who were unwittingly infected with the virus may transfer the disease to patients.
But researchers from the National Institutes of Health (NIH) tested blood samples from more than 250,000 donors and found only 0.001 percent included trace coronavirus DNA.
Even in rare cases where small amounts of coronavirus were present in a blood sample, the virus was not transferred to a new patient.
This is ‘good news for thousands of patients who may need a blood transfusion,’ says one of the doctors involved with the research.
A new NIH study found that only 0.001% of blood samples from donors to recipients contained trace coronavirus DNA (file image)
An estimated 6.8 million Americans give blood every year, according to the American Red Cross, with someone in the U.S. needing blood or platelets every two seconds.
A patient might require a blood transfusion for surgery, cancer treatment, chronic illness, and other injuries.
One condition, sickle cell disease, impacts 90,000 to 100,000 people in the U.S. – patients suffering from this disease require transfusions throughout their lives.
In spring 2020, the healthcare system shifted focus to COVID – while limited testing meant that many Americans worried they might have become infected with the coronavirus, but weren’t able to find out for sure.
This worry was especially concerning for blood donation clinics and patients waiting on transfusions. If a donor gave blood – without knowing they were infected – could they transfer the coronavirus to a patient?
Some spring 2020 studies showed low concentrations of coronavirus RNA in blood samples taken from hospitalized COVID patients, providing additional reason for concern.
To investigate the issue, scientists at the National Institutes of Health (NIH) set out to study blood safety at the national level.
They wanted to find how often the coronavirus was actually present in blood donations – and whether it could be transferred to patients.
The NIH team looked at blood samples collected between March and September, 2020.
Samples came from six major metropolitan areas: San Francisco, Boston, Minneapolis, Los Angeles, New York City, and Seattle.
Seattle was the first COVID epicenter in the U.S., and both New York City and Los Angeles would become hotspots during the collection period – meaning unidentified COVID infections were common in these cities.
To test samples more efficiently, the researchers used a technique called ‘pooling.’ They combined blood samples from multiple people and tested them together.
Pool testing allows scientists to test samples more efficiently, analyzing many samples at once. The NIH researchers found only three COVID-positive pools out of almost 18,000
If a pool tests negative, every sample included in the pool is assumed to be negative.
If a pool tests positive, scientists then re-test smaller groups of samples included in the pool in order to find the positive one.
In total, the NIH researchers tested about 18,000 pools, including blood donations from 258,000 people. Only three out of those 18,000 pools included any coronavirus.
That’s a rate of one in 100,000, or 0.001 percent risk of coronavirus presence.
When the researchers looked more closely at the COVID-positive samples, they found that very low levels of coronavirus DNA were present. Antibodies associated with an immune system fighting COVID weren’t present, either.
These findings mean that, even in the blood donations where trace coronavirus was present, a transfusion would be unlikely to transfer COVID to a patient.
No case of a patient getting COVID through a blood transfusion has ever been reported, the researchers note in a summary of these findings (published Tuesday in the journal Transfusion). This new study adds additional evidence to support the safety of blood transfusions.
‘This finding is good news for thousands of patients who may need a blood transfusion because of surgery or a disease that causes anemia, such as a rare blood-related condition or leukemia,’ said Dr Simone Glynn, chief of the Blood Epidemiology and Clinical Therapeutics Branch at the National Heart, Lung, and Blood Institute, which conducted the study along with another NIH agency.
Still, the researchers recommend that possible blood donors refrain from going to a donation clinic if they have COVID symptoms or have come into contact with anyone who recently tested positive.
‘It appears safe to receive blood as a transfusion recipient and to keep donating blood, without fear of transmitting COVID-19 as long as current screenings are used,’ said Dr Sonia Bakkour, a scientist on the study’s research team.