booster

Test and Trace Boss Tells Public Not to Socialise Unless Necessary

In an interview on BBC Radio 4’s Today Programme, Dr. Jenny Harries, the Chief Executive of the U.K. Health Security Agency as well as the Head of the NHS Test and Trace scheme, said that the public must not attend social gatherings if they “don’t particularly need to” in order to restrict the transmission of the Omicron variant. Harries also called on all those eligible to receive booster jabs to go and get one and play their part in the fight against Covid. WalesOnline has the story.

Dr Jenny Harries, Chief Executive of the U.K. Health Security Agency (UKHSA), told BBC Radio 4’s Today programme that people could do their bit by reducing the number of social contacts they have.

She said that even if our “vaccines appear to be effective, but we find that the variant is more highly transmissible, having lowish grade infection, but in very large numbers of the population, (it) could still be a significant impact on our hospitals.

“And of course, our behaviours in winter and particularly around Christmas we tend to socialise more so I think all of those will need to be taken into account.”

Asked about working from home, she said: “We’ve seen that not everybody has gone back to work and I’d like to think of it more in a general way, which is if we all decrease our social contacts a little bit, actually that helps to keep the variant at bay.

So I think being careful, not socialising when we don’t particularly need to and particularly going and getting those booster jobs which, of course, people will now be able to have at a three-month interval from their primary course.

Worth reading in full.

Stop Press: As of today, the Government has brought back mask mandates to a wide array of public settings. A full list can be found here.

Stop Press 2: The crackdown on non-mask wearers on the London tube has begun. MailOnline has more.

Stop Press 3: The Government has rebuked Dr. Harries and distanced itself from her remarks. According to the Telegraph:

Boris Johnson insisted “we’re not going to change the overall guidance, we don’t think that’s necessary”, when he was asked about comments by Dr. Jenny Harries, the Chief Executive of the U.K. Health Security Agency, who had urged people to avoid socialising “unless you need to” in the run up to Christmas.

Downing Street also heavily distanced itself from her remarks, with the PM’s official spokesman stressing: “It’s not our advice to the public currently. You’ll know the measures we set out at the weekend. The UK HSA is an arms-length body of Government, and Jenny Harries provides advice to the Government, she is not a Government minister. The public should follow the guidance as set out by the Government and indeed the Prime Minister at the weekend.

Conditional on Infection, the Vaccine May Not Protect Against Death in Over 60s

In a recent article, I noted that vaccine effectiveness against death may have been overestimated due to the ‘healthy vaccinee’ effect – the tendency for people who get vaccinated to be healthier and more risk-averse than those who don’t.

Likewise, Will Jones recently reported on a large Swedish study, which observed declining effectiveness against severe outcomes, particularly after six months. Discouragingly, the decline in effectiveness was most pronounced among older, frail individuals ­– the group most at risk from Covid.

Now a new study (which hasn’t yet been peer-reviewed) has made a similar finding. Maxime Taquet and colleagues analysed data from a large database of electronic health records in the U.S.

Their sample comprised ~19,000 individuals who’d had a confirmed SARS-CoV-2 infection between January 1st and August 31st 2021. There were two groups: those who had been vaccinated at least 14 days prior to infection, and those who had not been vaccinated prior to infection.

The two groups were matched not only on basic demographic characteristics, but also on a large number of medical risk factors. In addition, the unvaccinated individuals were selected from among those who’d ever received a flu vaccine. Overall, substantial efforts were made to ensure the two groups were comparable.

Taquet and colleagues’ main finding is shown in the figure below. The lines on each chart show the cumulative probability of death for vaccinated and unvaccinated people, respectively. (Note: they also looked at other severe outcomes; see Fig. 3.)

The chart on the left indicates that, on average, vaccinated people had a lower risk of death than unvaccinated people. However, as the other two charts indicate, this difference was seen primarily in those under 60. Among those over 60, it was small and not statistically significant. The authors note:

Receiving 2 vaccine doses was associated with lower risks for most outcomes. Associations between prior vaccination and outcomes of SARS-CoV-2 infection were marked in those < 60 years-old, whereas no robust associations were observed in those ≥ 60 years-old.

Why would vaccination have a stronger effect among those under 60? The researchers speculate that:

In younger patients, effective B-cell response to vaccination might be followed by infection with variants against which antibodies have less neutralising activity … In older patients, the B-cell response to vaccination might itself be ineffective

It’s important to keep in mind that their finding concerns the risk of death conditional on SARS-CoV-2 infection. To the extent to that the vaccine protects against infection, it will protect against serious illness and death too.

However, it’s still noteworthy that effectiveness against death in over 60s was minimal among those who had been infected. Of course, this is just one study, so it shouldn’t be given too much credence. But the researchers did make substantial efforts to ensure the two groups were comparable and thereby obviate the ‘healthy vaccinee’ effect.

If their finding is true, it would suggest that previous observational studies have overestimated vaccine effectiveness against severe outcomes in older age-groups. It would also suggest that most of the protective effect for these age-groups comes from immunity against infection, which we know wanes rapidly in the absence of boosters.

The evidence from Taquet and colleagues’ paper could therefore be taken as supporting voluntary boosters for high-risk groups, as well as the continued build-up of natural immunity in the rest of the population.