'Booster effect': Covid hospital admissions falling rapidly in patients over-75

In the 75 to 79 age group weekly Covid admissions dropped by 41% over the same period, while rising very slightly - from 242 to 246 - in all patients under 60.

Professor Linda Bauld, chair of public health at Edinburgh University, said: "It's pretty clear that the immune response to the booster starts to happen within the first week - within seven days - so I think we are seeing a booster effect.

"That's what Israel saw. Maybe I'm being too optimistic but the uptake is good in the older age groups."

Source: Public Health Scotland

Elderly care home residents were among the first to be offered boosters when the rollout began on September 20, with those over 70 in the community - starting with the oldest - invited to appointments at vaccination hubs during October.

To date 80.2% of over-80s, 87.4% of 75 to 79-year-olds, and 83.7% of 70 to 74-year-olds have had a booster.

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The data from PHS shows that while the over-80s continue to account for the largest number of Covid admissions - 91 out of a total of 561 in the week ending November 9 - this is down from 172 in the week ending October 19.

They have also shrunk as a share of total admissions over the same period - from 25% to 16%.

A similar pattern is seen in the 75 to 79 age group, with admissions falling from 91 to 54 and from 13% to 9.6% as a proportion of all admissions.

Source: Public Health Scotland

It comes days after research from the UK Health Security Agency indicated that protection against symptomatic infection in adults aged 50 years and over rose to 93.1% within two weeks of receiving a booster if they had previously had two doses of the AstraZeneca vaccine, and 94% if they had previously been vaccinated using Pfizer.

The boosters given are either one full dose of the Pfizer vaccine or a half dose of the Moderna vaccine, regardless of what patients previously received.

A reduction in the risk of infection was seen from as early as seven days after the booster.

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Confirmed Covid cases among adults over 75 in Scotland have been in steep decline since October 25 for females and October 26 for males.

Paul Hunter, a professor in medicine at the University of East Anglia, said: “It is too early to know how effective the booster will be in the UK to at reducing the risk of hospitalisation.

"But from the Israeli experience we can expect the booster to be even more effective at preventing severe disease than at preventing symptomatic infection.”

Patients over 80 are still at highest risk of hospitalisation in Scotland if they do become infected with the coronavirus, however.

By the end of October, 40% of people over 80 were being admitted to hospital within 14 days of a positive Covid test compared to a 4% infection-to-hospitalisation rate for the population as a whole.

Around 40 per cent of those over 80 and 20 per cent of those aged 75-79 were admitted to hospital within 14 days of a positive Covid test

There are also signs that the boosters are once again increasing the gap in the risk of infection between vaccinated and unvaccinated individuals, which came close to overlapping in October.

In the week ending November 12, the case rate among individuals vaccinated with two or more doses had fallen to 294 per 100,000 compared to 481 per 100,000 in the unvaccinated.

At the end of October, the difference had shrunk to just 300 versus 330 per 100,000.

The difference in risk of infection between vaccinated and unvaccinated has widened again after nearly converging at the end of October, when the trend was linked to waning immunity

The hospitalisation and death rates - adjusted to account for age differences - also continue to be nearly three times higher in unvaccinated individuals compared to those given two or more doses.

Earlier this week it was announced that boosters will be extended to all adults aged 40 to 49, with most expected to become eligible in December.

The jags are administered no earlier than six months from when patients received their second dose.

Prof Bauld said she would not be surprised if the rollout is eventually extended to all adults.

She said: "In the Pfizer trial they didn't have age limits - there were people of different ages over the age of 18 looking at boosters versus no boosters, and all age groups benefitted.

"The decision is for the JCVI, but given the international context where they're being delivered to all age groups, it certainly wouldn't be unusual for them to recommend that in future.

"But I think the approach they've taken is reasonable, to start with those most at risk."

Professor Lawrence Young, a virologist and professor of molecular oncology at Warwick University, added: "It’s likely that more widespread rollout of booster jabs to younger age groups will be needed to provide a higher level and longer duration of protection that will drive down transmission in the community.

"It also likely that we also need to further extend the vaccination programme to give 12 to 15 year olds a second jab and to consider vaccinating five to 11 year olds as has already started in the US and is about to start in Israel."

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It is unclear whether Scotland's vaccine passports - if extended to leisure and hospitality venues in December - will require those eligible for boosters to show they have taken it.

Earlier this week Prime Minister Boris Johnson told a press conference that “we will have to adjust our concept of what constitutes ‘fully vaccinated'”, as he confirmed that boosters will become a requirement on vaccine passports for international travel.

Deputy First Minister John Swinney has also indicated that ministers are considering whether to require people to show both proof of vaccination and a negative Covid test - rather than one or the other - to access venues.