Public Health

Debate between Huw Merriman and Philippa Whitford

Tuesday 30th November 2021 Commons Chamber

[Dr Whitford]

We are still seeing hospitalisations and deaths in people who are doubly vaccinated. The reason we are delivering boosters in all four health services is because that immunity is waning. What we are concerned about with omicron is that if it is able to immune escape, it could push us backwards. Therefore, we simply do not want it to become re-established and undermine the achievement that vaccines have made.

The British Medical Journal review, to which the right hon. Member for South West Wiltshire (Dr Murrison) referred, showed that masks had as big an impact as hand hygiene, so surely we should do both. Neither of them has a major economic impact. We are not talking about locking down. We are not talking about shutting businesses. We are talking about everyone trying to protect everyone else, so that they can continue to be active and continue to be out in society.

It is important to remember that even if our current vaccines were shown to be less effective against omicron, they would not have no impact. We already see that impact on delta with regard to spread: the reduction is only about 50% but it has markedly reduced hospitalisation and death. We would therefore still hope for that with omicron, so pushing vaccination and encouraging people to get boosted remains as important as it always was. Delta is still by far the most dominant variant circulating in the UK.

There is no evidence as yet of differing symptoms or severity, but one of the weaknesses of the data from South Africa is that the initial outbreaks were in students. Young people tend to get milder infections and we do not yet know what omicron will be like in an older or more vulnerable population.

We have one advantage in the diagnosis of omicron: the S gene, which is one of the three genes that common PCR tests look for, is missing. That means that rather than having to wait for genomic testing, which takes quite a long time, we get a heads-up or an early warning on the PCR test. There is a sub-group with S-gene dropout, which means that the chances are that it could be omicron. Those patients could be warned and their samples can then be sent for full genomic testing. In Scotland, a retrospective review of recent PCR results looking for S-gene dropout has identified the nine patients with omicron. I assume that similar work is happening in the other nations across the UK. In contact tracing of the nine patients, there is no evidence of a connection to either COP26 or the South Africa rugby game, but tracking continues.

PCR testing is, therefore, even more important. Lateral flow tests—which, hopefully, we are all doing regularly before coming here—cannot detect variants. It is a simple yes/no that someone does themselves, with no access to take further analysis. Lateral flow tests had been allowed as part of travel testing. In the Netherlands, 600 passengers arriving from South Africa were tested and one in 10 were found to have covid—an incredibly high incidence and much higher than we have anywhere in the UK—and a fifth of those cases were already omicron. Omicron is not just in southern Africa or in the UK. As a result of the use of lateral flow tests, it is probably already more widespread than we think. It is therefore welcome that today the Government returned to PCR testing for travellers rather than lateral flow tests, and that they are quickly re-establishing quarantine, but people should have a PCR test before they travel. It is rather like shutting the stable door if we find that someone is positive when they have just spent eight hours on a plane with hundreds of other people.

[Huw Merriman (Bexhill and Battle) (Con)]

Is the hon. Lady not concerned, as I am, that there is too much emphasis on PCR testing for tracking variants of concern? During a three-week period in July, there were 500,000 PCR tests, of which 7,000 were positive for covid. Only 5% of those 7,000 were tested for variants of concern, so this is not quite the silver bullet on variants of concern that she might hope it would be.

[Dr Whitford]

I was not claiming that it was, because genomic testing takes a couple of weeks generally and it is therefore too late for someone to isolate. What I am saying is that with this variant, as in alpha but not in delta, the missing S gene means that on that initial test—which takes six hours or until the next day, or whatever it is—we already get a heads-up that we are dealing with an omicron case. We can go on to do the genomic analysis, but we can say to the patient, “We think you have this variant. You need to isolate thoroughly and for longer.”