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expert comments on COVID-19 reinfections

In light of the news today that Prince Charles has tested positive for COVID-19 for the second time, here are some comments from scientists on reinfections in case useful.


Dr Simon Clarke, Associate Professor in Cellular Microbiology, University of Reading, said:

“The news that the Prince of Wales has tested positive for Covid-19 for a second time is a reminder to us all that anyone, no matter what your status in society, is potentially vulnerable to infection, or re-infection.

“Thankfully, we now know that those who are fully vaccinated, or who have been previously infected with other strains of the coronavirus, are in the best possible position to fight off the infection. He will likely have a good antibody level, but this does not guarantee immunity to infection and reduces, but does not eliminate, his risk of serious disease.

“No doubt the Prince of Wales will isolate at home as currently required by law and will want to avoid passing an infection to those in his family, particularly those who are more vulnerable than him. No-one wants to put any elderly lady in her 90s, including the Queen, at unnecessary risk of catching the virus.  This is a stark example of why the government’s plan to drop the compulsion to self-isolate when infected, is so careless.

“While we don’t know which variant of the virus Prince Charles has, it will almost certainly be Omicron, which accounts for most UK cases at present. Omicron has been shown to be less lethal than delta, but it has led to hospitalisations and deaths.

“Now that more than a quarter of the UK population has been infected at some point in the past, it is likely that reinfections, which already account for around one in ten cases, will grow as a proportion of the number of new cases each week. We are only just learning what impact this will have on people’s health in the long term.”


Professor Lawrence Young, Virologist & Professor of Molecular Oncology, University of Warwick, said:

“Recent data shows that infection with previous covid-19 virus variants provides around 60% protection from reinfection with the omicron variant.  A combination of waning immunity after vaccination and the ability of omicron to partially escape vaccine-induced immunity means that two doses of a covid vaccine provides at most 10% protection against symptomatic infection at 5 to 6 months after the second jab. A third booster jab increases protection from symptomatic omicron infection to 60-75% at 2 to 4 weeks after vaccination but this falls to 30-40% after 15 weeks. But protection from hospitalisation remains high after the booster jab – around 90 over the first few weeks dropping to 75% after 10-14 weeks. It is likely that a combination of previous natural infection and full vaccination will offer higher levels of protection for a longer period.”


Prof Jonathan Ball, Professor of Molecular Virology, University of Nottingham, said:

“Reinfections, even in those people who have been fully vaccinated, can be expected. As antibody levels wane or following the appearance of a new variant – like Omicron – your levels of antibody immunity are not sufficiently high to prevent infection.

“That’s different from having no immunity though. Your body has stored up a population of memory cells – both antibody-producing cells and T-cells – which on encountering this new infection, will proliferate rapidly then start fighting off the virus before it can cause serious disease.

“We never expected immunity from vaccines or natural infection to protect you from infection indefinitely, but we did hope that they would protect most people from serious disease. That’s holding up.

“But we should remember, there are many people – those severely immunosuppressed especially – for whom the vaccines may not give the levels of protection we would like. So, it’s important that the government and department of health deploy an effective strategy to protect these people. For example, regular testing and isolation for those people working or caring for them, and regular testing for those affected so that they can seek appropriate antiviral treatments as soon as possible. This will be especially important as we start to lift all restrictions.”



All our previous output on this subject can be seen at this weblink:



Declared interests

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