Live updates: follow the latest news on Covid-19 variant Omicron
The UK government on Monday outlined its strategy to contend with the “new kid on the block” — the Omicron Covid-19 variant.
Already travel bans have been imposed on countries in southern Africa where Omicron was first identified, and PCR testing reintroduced for everyone entering the UK, regardless of their vaccination status.
Britain's Deputy Chief Medical Officer Jonathan Van Tam emphasised “the very high degree of current uncertainty in our knowledge".
“There are far more things we don't know yet than things we do,” he said, although he revealed “heightened concerns” over the variant's ability to evade vaccines.
While Omicron has an “elevated growth rate” compared with its viral antecedents, Prof Van Tam said it as yet unclear whether this meant it was more transmissible.
With so many unknowns and imponderables, formulating the most effective response at both national and international level is challenging.
However, by combining the history of coronavirus with the principles of vaccinology and immunology, scientists from the UK's Joint Committee on Vaccination and Immunisation have formulated five recommendations to combat the Omicron thread.
1. Extend Covid booster programme to all adults aged 18 and above
The importance of a booster has never been greater, according to Professor Wei Shen Lim, Covid-19 Chair for JCVI.
“From what we know about the Omicron variants so far, it may be that the vaccines that we have at the moment may be less good than against the current circulating Delta variant,” he said.
Yet far from marginalising the current vaccine crop, he said it made it all the more important people “increased the strength of their immune response” by being boosted with them.
The rationale is simple: the more antibodies someone has in their system, the stronger their immune response will be, even in the event of a vaccine-variant mismatch.
To date, 17,896,864 out the 68.4 million people in the UK have received their booster or third doses, showing the race to get boosted is well and truly on.
2. Prioritise Covid booster shots by risk and reduce dose gap
The UK's health service vaccine programme has always used risk as its prioritisation metric. In other words, those most at risk such as the elderly and those with underlying health conditions have been prioritised for vaccination.
Prof Lim said this approach would now be applied to the booster roll-out.
“We have not seen any data to suggest a new variant is in any way different from previous in terms of who is most at risk of severe disease,” he said.
“As we know the elderly and [people with] underlying health conditions are at higher risk of severe disease. And so we want to protect them as a priority.”
Prof Lim also said the gap between receiving the second dose of a vaccine and a booster will be reduced to three months from five.
The shortened time frame is based on concerns over a new Omicron-spawned wave washing over the UK before much of its population has a sufficient number of antibodies.
“With any vaccine during a pandemic, we get the greatest benefit both for individuals and society if the vaccine is deployed before the wave starts,” said Prof Lim.
“I'm not predicting that there will be a wave of the new variant but should there be a wave, we want to be in the best possible position.”
3. Severely immunocompromised to get Covid booster now
People with severely compromised immunity were placed on a different vaccine schedule to those with more normal immune responses at the start of the vaccine roll-out.
Most of this cohort will already have received three doses, and for them, the booster shot will be their fourth.
Prof Lim said the booster should again be received no sooner than three months after their last primary dose.
4. Pfizer or Moderna the preferred booster shot
The UK continues to mandate the use of the Pfizer, AstraZeneca and Moderna vaccines.
Dr June Raine of the Medicines and Healthcare products Regulatory Agency, said all had “overwhelmingly positive benefit risk balance in their licence to use.”
Only Pfizer and Moderna of the three are being recommended as Covid boosters.
This has nothing to do with the furore around blood clots allegedly caused by the AstraZeneca vaccine, and everything to do the strength of the immune response generated, which is greater in the two mRNA vaccines.
Prof Lim said those unable to have mRNA vaccines should still have the AstraZeneca jab as their booster as it gives a “good boost” and the JCVI would rather people have a boost than none at all.
5. Children aged 12-15 to get second vaccine dose
The issue of vaccinating children has become a cause celebre for those who believe the government's Covid-19 response has been a case of overreach.
Undeterred by the sceptics, the JCVI is now recommending that children between the ages of 12 and 15 are moved on to the same vaccination schedule as those aged 16 and 17.
This means they will receive 30mg of Pfizer, 12 weeks after their first dose.
“We are closely watching the emerging data on Omicron, and if there is a need to advise that the dose interval between doses one and two for children should be altered, then we will do so,” said Prof Lim.