Scientists have warned that a new wave of infections has begun as two sub-variants of Covid led to a surge in cases.
According to the latest figures from the Office for National Statistics (ONS), more than 3.8 million people have contracted the virus in the UK, a weekly increase of 7 per cent.
This growth is largely due to omicron options BA.4 and BA.5, according to the ONS.
More than two years after the first cases in the UK, millions of Britons have contracted the virus, and some have contracted it multiple times.
But how likely is re-infection and what protection do vaccines and boosters offer?
Here’s everything you need to know.
How common are repeated covid infections?
When the Omicron variant hit the UK last December, re-infection rates rose 15-fold.
Omicron’s extensive mutation allowed the virus to overcome established immunity, scientists believe.
This is why so many people who have been vaccinated or had the virus get it again at Christmas.
This was told by Danny Altman, professor of immunology at Imperial College London GuardianOmicron is “poorly immunogenic, meaning that catching it provides little to no additional protection against reinfection.”
Although the new BA.4 and BA.5 variants come from the Omicron line, “there is now additional evidence the very marginal ability of the previous Omicron to generate any immune memory for BA.4 or BA.5,” said Professor Altman.
This suggests that even if you had Omicron during the Christmas and New Year wave, you can still catch the virus again.
Professor Tim Spector, who hosts ZOE Covid app told Guardian: “There are definitely a lot of people who had Covid earlier in the year who got it again, including some with BA.4/5 who had BA.1/2 just four months ago and who thought will be protected. .”
However, the professor added that re-infection with Covid within three months is “rare”.
What if I have been vaccinated?
The new BA.4 and BA.5 variants contain mutations not present in the early Omicron strains.
So even if you’ve been vaccinated and revaccinated, you’re still vulnerable to the new subvariants.
Researchers from China reported in the journal Nature that the new subvariants “significantly evade neutralizing antibodies induced by SARS-CoV-2 infection and vaccination.”
Vaccine boosters based on the BA.1 virus, such as those developed by Pfizer/BioNTech and Moderna, “may not achieve broad-spectrum protection against the new Omicron variants,” the researchers warned.
“My personal bias is that while there are some advantages to having an Omicron vaccine, I think it would be a minor advantage compared to keeping existing vaccines and boosters,” said Dr. Onyemo Ogbuagu, an infectious disease researcher of Diseases from Yale University. School of Medicine in New Haven, Connecticut.
“Despite the suppression of immunity, vaccines can still be expected to protect against serious diseases,” said Dr. Ogbuagu.
“If you have to make a booster, make one. What we’ve learned clinically is that it’s very important to stay up-to-date on vaccines.”
How severe will my symptoms be if I get reinfected?
As a rule, infections are easier the second or third time because of the residual immunity developed in the body.
However, according to preliminary data from Professor Kei Sato and his colleagues at the University of Tokyo, the new subvariants may have evolved to favor infection of lung cells rather than upper airway tissue.
This makes them more like the earlier and tougher versions of Alpha and Delta.
Dr Stephen Griffin, a virologist at the University of Leeds, said: “It looks like these things switch back to a more dangerous form of infection, so they go down into the lungs.”
While it is too early to say whether symptoms will be more aggressive in cases of re-infection, the risk of these new Omicron variants is “potentially greater than the original BA.2”, Professor Sato said.