Plan B: what are the new Covid rules and when do they start?

The new measures will be reviewed on January 5 and are due to expire on January 26 if the government concludes they are no longer necessary.

Are Christmas parties allowed this year?
Christmas parties and nativity plays can still go ahead under the new rules and it appears that further restrictions on gatherings are unlikely to be introduced this year. Boris Johnson has insisted that “Christmas should go ahead as normally as possible”, while urging the public to “exercise due caution”. Several big companies and government departments have already cancelled their Christmas parties and those holding large events will have to follow the new Covid pass requirements.

• Johnson imposes plan B restrictions
• New variant ‘much better at evading body’s defence system’

What about pubs and restaurants?
Most hospitality settings such as pubs and restaurants will not be affected by the new rules. Face coverings will not be required as the government has made an exemption for “venues where it is not practical to wear one, such as when you are eating, drinking or exercising”.

Do vaccine passports work?
It depends on what you’re hoping to achieve. In France, where they have been required in a wide range of settings, they did seem to encourage people, especially younger people, to get vaccinated. But the UK government’s scientific advisers have told ministers that they have “limited evidence for the direct impact of certification on population level rates of infection and/or severe disease”.

One problem is that vaccinated people can still be infected and spread the bug. A system that requires people to have had a recent negative test could be better at reducing transmission. Sage has also warned that a passport system may entrench the views of people who are already sceptical about vaccines.

What about working from home?
The Scientific Advisory Group for Emergencies (Sage) has advised ministers that “working from home is one of the most effective measures available at reducing contacts”, saying it had a “strong impact on transmission and R [rate]”. It means people spend less time in offices and other workplaces where social distancing can be difficult. Use of public transport falls, as do post-work trips to the pub.

A study carried out in England and Wales during the second wave estimated those who went into a workplace or place of education during this period had a 15 per cent risk of being infected, compared with 9 per cent for those who did not, although rates of vaccination were lower than now. The downsides are that it is only possible for about half the workforce and it damages businesses, including those that cater to workers.

Why is the government moving to plan B?
For weeks it will seem as if this has all been a fuss about nothing. This variant is a pandemic within a pandemic. For all the talk about Omicron, Britain is still in the middle of a very big — but manageable — wave of Delta. Against these 50,000 daily Delta cases, 1,000 of Omicron, then 2,000, then 4,000 will barely register. As restrictions tighten and behaviour changes, overall cases may even fall — it won’t take much to push the R rate of Delta below 1. Omicron could be swamped, and hidden.

However, as Johnson stressed at a Downing Street press conference, Omicron is doubling every two or three days. By Christmas most scientists expect it to have become the dominant strain. Then, in January, after hiding beneath the waters of Delta, the fear is it will burst through and cases will again rise so high that the NHS will be in danger.

Sajid Javid, the health secretary, said that the measures were necessary to “buy time” as he warned that there could be a million Omicron infections by the end of the year. “I hope that people will understand that by taking decisive action now, we can potentially avoid action later,” he added.

If plan B does not stop Omicron spreading altogether, what’s the point?
The government now has a big strategic choice. Will slowing the spread of Omicron be enough, in Johnson’s famous analogy from March last year, to “squash the sombrero” and spread out cases to prevent so many people becoming ill at once that hospitals cannot cope? Or does it need to revert to suppressing the virus? The hope, as the prime minister made clear at the press conference, is that a ramped-up booster programme will mean mitigation is enough. But until we have more data, we will just be guessing.

What is South Africa telling us? Are people getting sicker?
The early data — and it is very early, with South Africa only a couple of weeks into its Omicron wave — has not produced any sign that the variant causes worse disease than previous strains. One analysis has shown that there is no increased risk of hospital admission. There are anecdotal reports of most cases being mild.

But the South African scientists gathering this data stress that it is still early days. It takes two to three weeks to become seriously ill and hospital admissions are rising very fast — by about 300 per cent in the past week, Chris Whitty, the chief medical officer for England, said at the Downing Street press briefing. So far patients in South Africa appear to be younger than in previous waves but there is no guarantee that this will continue. “It is too early for us to be absolutely confident about hospitalisations,” Whitty added.

If it does cause less serious infections, does it matter if it evades immunity?
The maths is depressing, and inexorable. In a phrase that has now become a go-to mantra of epidemiologists, a small proportion of a big number can still be a big number. The vaccines will never be perfect. So even if Omicron is less intrinsically severe, even if vaccines provide a big chunk of additional protection, if enough people get infected, then the risk remains of hospitals being swamped. As Whitty noted, the NHS is already “incredibly busy” with work not involving Covid.

Why does Omicron spread quicker?
There are two ways a variant can gain an advantage. One is by transmitting more easily between people, the other is by having more people to transmit to. It may be that Omicron is more transmissible, but it is now certain that it is better at evading immunity. A real-world study in South Africa found that it appeared to cause two-and-a-half times more reinfections. A laboratory study found that antibodies from vaccination had a 40th of the potency against Omicron.

The findings come from blood sera experiments involving just 12 people. It is a measure of how little we know that this small experiment will now be discussed in governments around the world.

A 40-fold drop in antibodies sounds scary
The experiments involve taking the blood of vaccinated people and continually diluting it to find the minimum concentration that will still stop infection in a petri dish. Because of the way this kind of experiment is conducted, it always finds efficacy falls that are several-fold.

These numbers are a good proxy for vaccine efficacy but don’t transmit across intuitively — it does not mean the vaccine is a 40th as good. The work also only looks at so-called neutralising antibodies, which recognise the viral spike, latch on and then prevent it entering a cell. Once a cell is infected there are other wings of the immune system that prevent severe disease and are likely to be far less severely affected.

Will vaccines hold up?
It now seems inevitable there will be more infections and more reinfections. Few immunologists would be surprised if there was a 30 to 40 per cent hit on efficacy in preventing infection.

We simply don’t have good data on how well vaccination will prevent serious disease. One sign of hope in the South African laboratory study was that people who were infected and double vaccinated had comparable immunity against Omicron as those who were merely double vaccinated did against Delta. This is an indication that a booster dose could provide the protection needed to get through winter.

It’s important to remember that the neutralising antibodies weren’t rendered completely ineffective. Professor Willem Hanekom, director of the Africa Health Research Institute, which ran the study, said: “The drop [in antibodies] was pretty impressive but it wasn’t complete, and that’s very important to see. There wasn’t a complete absence of neutralisation — neutralisation was still happening. The primary reason why we give vaccines is to protect against severe disease and death — and we believe that this is still going to happen.”

A separate study, by the creators of the Pfizer jab, has suggested that three doses should offer “significant protection” against Omicron.

How do we get through the winter?
In the past fortnight many of the fears of the scientists who discovered Omicron have been confirmed. But so many unknowns remain. Johnson said at the press briefing that he hopes to review the plan B measures no later than early January but it will be at least Christmas before we truly have an idea of the threat posed.

Until then, implementing plan B might slow the spread. It won’t stop it. Our best tool, as Whitty stressed, remains boosters and in the longer term it is increasingly likely we will need tweaked vaccines for a fourth dose. In the meantime the government will be looking at ensuring that even in the worst case schools never close again.