January 24, 2021

TPT News

Voice Of India

Could a Covid vaccine bring back normality?

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With test and trace a shambles, many are pinning their hopes on a jab. But experts warn more measures will be needed to vanquish the coronavirus

England is back in lockdown. It happened not a moment too soon. As of 2 November, almost three-quarters of a million new cases have been officially counted since 21 September, when the government’s scientific advisory committee Sage advised lockdown.

On that day, Britain had only had about 360,000 cases since Covid arrived. Now the figure is three times that. So many more cases mean it will take longer, and possibly require tougher social restrictions, to get numbers down by imposing lockdown than it would have in September, says James Naismith, head of the Rosalind Franklin Institute in Oxford.

Naismith calculates that we will have 500 deaths per day in two to three weeks because of the cases that occurred over the past week, compared with an average of 144 in the week ending 2 November.

But it could be far worse. If we had done nothing for another two weeks, he says, we’d be looking at 1,000 deaths a day by Christmas – and more, if hospitals fill up and not everyone can get optimal treatment.

“No one is saying lockdowns are not harmful, they will cause misery and death,” says Naismith. “Being poorer as a country means we will be unhealthier. We know despair and isolation take lives. We know delays in treating some (non-Covid) diseases will increase deaths.” It is clear, however, that Covid-19 is far deadlier, he says.

But beating it back means people must follow the lockdown rules, and more closely than many did in spring. And that will be easier if there is a light at the end of this tunnel.

The brutal truth is that Boris Johnson’s pledge in July that Covid would be “over by Christmas” is as illusory as that promise proved back in the first world war.

But we know that places that acted fast and forcefully enough to get an infection down to low levels early on, then kept it there, with some distancing but also effective testing, tracing and quarantine, have been able to return to a degree of normality.

Life is largely normal in New Zealand; the South Korean test and trace response are widely regarded as the benchmark; Taiwan recently celebrated 200 days without a case; Vietnam hasn’t added to its death count of 35 since 5 September, and China, source of the virus, has so far avoided a second wave.

But given that the UK’s test and trace system is so shambolic, we appear to be relying on a vaccine to bail us out. Sadly, it’s more complicated than that. Even once discovered, manufactured and distributed, it won’t banish the virus immediately, says Prof David Salisbury of Imperial College London, a former director of immunisation at the Department of Health.

We will still need some distancing, and testing and quarantine to keep outbreaks under control. But we may not be condemned to the life we’re living now.

Vaccines

A vaccine may not be enough on its own, but it is necessary. It is the only proven way to reach “herd immunity” – when so many of the population (thought to be at least 60% for Covid-19) are immune to the virus that an infected person contacts very few non-immune people and, unable to find new hosts, the virus dies out.

Testing for a vaccine in a laboratory in Beijing.

Letting the virus rip through a population with less immunity – as advocated by the so-called Great Barrington Declaration and others – would kill thousands who would have been saved if we had slowed the spread of the virus before the vaccine arrived, overwhelm the NHS and leave many people dealing with the misery of “long Covid” for years to come.

We will know before the year’s end whether some of the 11 vaccines now in large-scale trials actually work. The US-based firm Pfizer and its partners are among the farthest along the track, partly because their vaccine is made of mRNA that codes for a virus protein, which is quick to produce.

Pfizer has nearly completed signing up 44,000 people for its vaccine, which requires two jabs four weeks apart. Half will receive a placebo. It hopes that by late November sufficient numbers of the participants will have caught Covid, and significantly fewer of them will have had the vaccine than a placebo.

If there are so few that it shows the vaccine made people half as likely to get the disease, the vaccine will meet the minimum level of effectiveness set by the US regulatory agencies. If there are so few that it shows the vaccine protected 77% of recipients, the trial will stop, as it would not be ethical to keep giving people placebo – and approval can get underway.

In documents shared last week, the head of the UK vaccine task force Katie Bingham revealed that the plan is to offer a vaccine to all adults over 50 by Easter next year.

Then what? Say the first vaccines protect 70% of the people who get them, and 70% of the population is vaccinated – and both of those are ambitious targets. That means 49% of the population will be protected, says David Salisbury.

Herd immunity requires more than that. It may even be difficult to vaccinate that many if side-effects such as fatigue, however mild or temporary, set in after the first jab and some refuse the second.

But current UK vaccination plans don’t aim for herd immunity at first. The most recent advice calls for “targeted” vaccination of people most at risk: frontline workers such as medical staff, and people who are older or have medical conditions such as diabetes, who are most likely to contract the severe disease.

Vaccinating those people would cut severe cases, deaths and hospital demand, but they don’t number enough to reach herd immunity. “The virus will continue to circulate among younger healthy people, especially if they ignore social distancing and won’t wear masks,” says Salisbury – at least until more people are vaccinated.

We will need what he calls “Vaccine Plus”, masks and some distancing, to keep this circulation in check – and stop it reaching the 30% of vaccinated, high-risk people who aren’t protected by the vaccine.

A wedding in Seoul, South Korea, in October.

Moreover, warns Peter Hotez of Baylor College of Medicine in Texas, the first vaccines might stop vaccinated people getting sick, but not prevent them from catching and transmitting the virus. “In that case, we’ll still require masks and social distancing, until better vaccines come along,” he says.

Some immunologists think that is not all bad. If young children – who do not usually get so sick from Covid as adults – start catching the virus every winter we may develop enough immunity, if not to stop the virus circulating then at least to limit its impact.

In a generation, everyone will have had it as children, and Covid will be mild. That may be what happened with the four coronaviruses that now cause common colds in winter. Genetic analysis shows one, OC43, left cattle and entered humans around 1890.

It may be what really caused a pandemic that year of what we thought was severe flu, says Nicholas Christakis of Yale University, but which we now realise had Covid-like symptoms.