There is “really good” evidence building that people who contract COVID-19 build up a strong resistance to reinfection, according to Professor Luke O’Neill.

On The Pat Kenny Show, the Chair of Biochemistry at Trinity College said it will take months to answer the question of COVID immunity; however, there are encouraging indications now coming through.

“There is good news here,” he said. “We have been wondering over the last few months – if you have had it, can you catch it again?

“There were kind of anecdotal reports of people getting re-infected but it turns out the evidence now suggests you will be protected or at least you won’t get as severe a disease next time.”

He said the evidence is “building up over time of course and it looks really good.”

“The CDC (Centres for Disease Control), that great body in the US, they made a statement that said there are no confirmed reports of a person being re-infected after three months,” he said.

“That is the first clear statement that there is no evidence you can get re-infected.”

Fishing

Dr O’Neill said a new study of a fishing vessel in Seattle, carried out at the University of Washington, also suggests that people who were previously diagnosed with the virus retain antibodies that protect against reinfection.

The owners of the boat tested the entire crew for the virus before they set out on a long-term voyage.

None tested positive; however, three showed evidence of neutralising antibodies.

Two weeks later a crew member was returned to shore after coming down with the virus.

After the crew was tested again, it turned out that 85% had contracted COVID-19; however, the three who were previously infected did not test positive or show any sign of symptoms.

Resistance

Professor O’Neill said: “104 people out of 122 got infected on this fishing vessel so that shows how contagious the virus is.

“But three who didn’t had very high levels of antibody and did not get infected a second time because they were infected before.

“So, there is our first really nice piece of evidence that if you have been infected, you won’t catch it again.”

He said the research is just a small study that needs to be replicated but noted that “to me and many people this is the first piece of scientific evidence that, if you have had it, you should be protected.”

T Cells

Meanwhile, a third study has found that, while antibodies can fade over time, people who have contracted the virus develop T Cells that can hunt it down if they get exposed again later.

T Cells can remain in the body for years and can provide long-term immunity.

There are also hopes that people who have developed T Cells from fighting off other coronaviruses - such as the common cold - may be armed with T Cells that provide resistance to COVID-19.

You can listen back to Professor O’Neill’s conversation with Pat here: