Coronavirus: Growing evidence that vaccines are stopping infections as well as deaths

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PREMIUM

TEN weeks after the UK became the first country in the world to administer a Covid vaccine outside of clinical trials, we are finally seeing signals of its real world effects.

Over the course of the past three weeks, the number of deaths recorded among over-85s in Scotland fell by 45 per cent, from 191 to 105 in seven days to last Sunday.

We know this cannot be fully explained by lockdown measures because it significantly outstrips the 13% decrease in Covid mortality among younger age groups over the same period (there were 218 deaths last week in patients aged one to 84, compared to 252in the week ending January 31).

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The data also dovetails with the time we know it takes both vaccines to induce a protective immune response: around 22 days for the Oxford/AstraZeneca, and 15-21 days for the Pfizer/BioNTech.

The latter has been predominantly used among older care home residents and deaths in this group can be clearly seen dipping from the very beginning of 2021, exactly two and a half weeks after 90-year-old Annie Innes became the first care home resident in Scotland to receive the jag.

Deaths among care home residents and over-85s are falling faster than in other groups

Meanwhile, the graph for deaths among all over-85s shows mortality falling from January 25 – exactly three weeks after the rollout of jags to the over-80s, starting with the oldest, began on January 4.

Similar patterns are also emerging in England, where Covid deaths have been falling faster among over-80s than under-80s – a pattern not seen during the first lockdown in 2020.

It is, as First Minister Nicola Sturgeon put it, “strong and compelling evidence that vaccination is starting to work”.

None of this is surprising, of course. Clinical trials had clearly demonstrated that severe disease and death were all but eradicated among the vaccinated compared to the non-vaccinated (caveat being that vaccine trials include fewer older and vulnerable people as a proportion compared to the general population).

However, what is arguably even more exciting is the growing evidence in favour of spacing doses 12 weeks apart, as the UK has done, and tantalising signs that the vaccines are effective not only in preventing disease, but infection.

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A peer-reviewed paper published in the Lancet yesterday, based on results comparing 9000 vaccinated and unvaccinated healthcare workers at Israel’s Sheba Medical Centre, shows that a single shot of the Pfizer vaccine is 85% effective at preventing Covid disease.

This is based on an analysis of symptomatic infections occurring between 15 to 28 days after the first dose (meaning that it is both unlikely staff were incubating the virus prior to inoculation, and too soon for the second booster dose – at day 21 – to have taken effect).

Israel, which is using the Pfizer vaccine and began inoculating over 60s first, has seen effects on cases and disease linked to the first dose

Professor Eyal Leshem, director of Sheba’s Institute for Travel and Tropical Medicine who studied infectious disease at Glasgow University, told Sky News: “This is the first real-world evidence of effectiveness that shows up after the first dose of the vaccine.

“We had some hints from the clinical trials and some calculations that were made based on the clinical trial [but]this shows early effectiveness, even before the second dose was administered.”

It comes after the latest evidence for the Oxford vaccine indicates that a single standard dose provides 76% protection against disease for the first 90 days after vaccination, with protection not dipping during this time frame.

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This climbed to just over 82% if a second booster dose is administered at 12 weeks but, curiously, if it is administered earlier – within six weeks – protection actually declines to around 55%.

Paul Hunter, professor in medicine at the University of East Anglia, said: “Taking all this evidence together, the 12 week gap between first and second dose is clearly the better strategy as more people can be protected more quickly and the ultimate protective effect is greater.”

Israel, which has the world’s fastest vaccination programme, started to see a decline in critically ill patients once 80% of over-60s were vaccinated

Furthermore, Israeli data for the Pfizer vaccine indicates that overall cases of the virus – including asymptomatic infections – were reduced by 75% after a single dose, meaning that people are not only less likely to become sick but crucially, less able to contract the virus and pass it on.

Researchers behind the Oxford vaccine have also reported that it appears to cut overall cases by 67% after a single dose.

This is good news for anyone desperate for a return to normality sooner.

We knew vaccinations were crucial to easing pressure on the NHS, but if they also substantially reduce transmission then cases should begin falling faster than from lockdown measures alone.

If vaccinated older Scots are less likely to become infected and spread the virus, that could help offset other transmission pressures such as schools reopening.

The trend in Israel may be a guide for how the pandemic will unfold in the UK over the next six months

By early May, everyone over 50 and younger people with health vulnerabilities – who combined account for more than 90% of all Covid hospital admissions in Scotland during the pandemic – should have had a first dose, with many of the oldest having had second doses by then.

All over-18s should be vaccinated in the summer, at which point – potentially – the virus should be running out of new people to infect: the all-important herd immunity threshold.

The risk remains, however, that easing restrictions too quickly could enable a surge in cases among the unvaccinated which enables vaccine-resistant variants to evolve and thrive, forcing us backwards.

For that reason, the routemaps out of lockdown which the Holyrood and Westminster governments unveil next week will be cautious.

Overseas travel is likely to be restricted for at least six months to avoid imports, but pubs and restaurants could be trading again by May, albeit with limits on household mixing.

“It may well be that by the end of May, we’re in a very different country than we are today,” told Professor Neil Ferguson, the epidemiologist whose worst case scenario of 500,000 Covid deaths triggered the first lockdown, told BBC Radio Four yesterday.

“We will still have rules in place but society will be a lot more normal if things pan out the way we think they will, and as the current data suggests they will.”

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