The emergence of a new, “highly infectious” variant of Covid — responsible for more than 40 percent of cases in the US, where hospitalizations reached more than 40,000 a day in December — is a grim reminder that the pandemic is far from over.
It comes as concerns grow about the effects of China reversing its zero-Covid approach, leaving its vast population, which has little natural immunity to the virus, able to resume normal life and travel.
Even here, despite most of the population getting booster after booster, there are around 9,000 people in hospital with Covid in England alone. That’s up from 4,900 at the start of December, according to NHS figures.
So will we ever wave goodbye to this pandemic?
Locked away in a laboratory in Bangladesh is a canister of white powder developed by scientists at Lancaster University that could prove to be a key weapon in helping us do just that.
Even here, despite most of the population getting booster after booster, there are around 9,000 people in hospital with Covid in England alone. That’s up from 4,900 at the start of December, according to NHS figures
This is because this powder, when mixed with saline, can be used as a vaccine against Covid-19. But unlike current Covid vaccines, it’s not injected into your arm: it’s sprayed into your nose.
Crucially, while other vaccines reduce the risk of serious illness and death, the hope is that this one, called ViraVac, will be more successful in reducing the risk of infection in the first place. This could represent a sea change in the approach to vaccinating against Covid – and potentially other respiratory viruses.
ViraVac is based on a vaccine sprayed around barns to stop a form of the coronavirus in chickens. It is one of about a dozen nasal Covid vaccines in development.
One of these involves a two-dose nasal vaccine now manufactured in India and developed by the University of Washington in the US and approved in India as a primary vaccine and as a booster. The vaccine was given emergency approval after studies showed it gave “full protection” against certain strains of Covid after six weeks.
All over the world, scientists are scrambling to perfect their own nasal vaccines – because the more we learn about the virus, the more some believe that targeting the immune system in this way is the best chance of halting the march of Covid for good.
Crucially, while other vaccines reduce the risk of serious illness and death, the hope is that this one, called ViraVac, will be more successful in reducing the risk of infection in the first place. Stock image used above
With the standard shot, protection varies depending on the vaccine and the variant it’s up against. For example, Moderna’s booster offers an impressive 90 to 95 percent protection against hospitalization with a Covid-19 infection nine weeks after vaccination, according to data from the UK’s Health Security Agency published last January. But protection drops when it comes to catching Covid – while it offers 63 per cent protection against the BA.1 Omicron variant and 70 per cent against BA.2 after two weeks, after 25 weeks this drops to 9 per cent protection against BA .1 and 13 on hundred against BA.2.
“One of the drawbacks of current vaccines is that they don’t provide long-term protection – we rely on multiple boosters – and they don’t prevent transmission of the virus or block infection,” says Laurence Young, professor of virology at the University of Warwick.
Muhammad Munir, professor of virology and viral zoonoses at Lancaster University, believes nasal vaccines offer a solution because they “stop community transmission” — in other words, stop people getting Covid and passing it on.
“This offers a chance to fully address this pandemic,” he says. Central to this is the fact that nasal vaccines act on different parts of the immune system compared to vaccines given intramuscularly (ie, as an injection usually given in the arm).
Professor Munir says that since Covid enters the body through infected droplets, which enter mainly through the nose or mouth, the logical approach is to focus the immunological fight there. As he explains, vaccines given in the arm produce T-cells (which knock out infected cells) and B-cells (which produce antibodies that attack invading pathogens).
“But these immune cells are mostly in the circulation and organs, with only a small amount in the nose and mouth, so they don’t guard the point of entry.
“Yet for Covid, the route of transmission is through the nose and mouth. This area is covered by a mucous membrane that continues to the intestine and is enriched with an arsenal of immune cells.
“If the vaccine is inhaled or given as drops through the nose or mouth, then it will prime these cells, which are the first line of defense, to act quickly.”
T cells and B cells in the lining can mount a blitzkrieg attack “almost the moment the virus gets in,” attacking it before it has a chance to infect cells, he says. “These nasal immune cells start working after a few minutes – whereas the immune cells created by intramuscular vaccines start working six to eight hours after the virus enters.”
This time difference, he says, is vital. “If just one virus particle successfully sticks to a cell, it takes over that cell and replicates to produce a million more viruses within an eight-hour cycle,” said Professor Munir, who led Lancaster University’s nasal vaccine research.
“That’s why the nasal vaccine will have the advantage – the immune cells it produces in the nasopharyngeal area can act immediately.” It’s a bit like the police sitting around waiting for a crime to be committed.
“With the intramuscular vaccine approach, the police only come when the problem is there, and by then the damage may have been done.”
Certainly, animal studies of his nasal vaccine look promising.
A study published in the journal iScience in August 2021 found that hamsters given it had “complete protection” from lung infections and inflammation — and did not shed virus particles when infected with Covid, which suppose it will stop further infection.
Reducing transmission is an attractive proposition, not only to reduce cases, but also because it can prevent prolonged Covid.
Continued high transmission also leaves the door open for more variants of the virus – currently, for example, the new variant XBB.1.5 is already responsible for one in 25 cases in the UK. “The fact that we haven’t stopped the transmission is why we’re in our tenth variant of anxiety,” says Professor Munir. “The emergence of this newly discovered variant of Omicron – which is worrying because we still don’t know how protective current vaccines will be – shows the importance of this, and there may be more around the corner.”
It’s not just Covid: the scientific community is buzzing about nasal vaccines against respiratory infections and the mucosal immunity they offer, says Professor Peter Openshaw, an immunologist at Imperial College London.
“I was on a [vaccine] a recent conference where every fourth presentation argued for the importance of mucosal immunity rather than systemic immunity [i.e. body-wide] — and that’s a big change.
If you can stimulate a good immune response in the mucosal layer, the immune cells in the nose can then travel around the rest of the mucosal layer down to the intestinal mucosa, Professor Young adds.
He says that this protection in the gut lining against Covid in particular may have unexpected benefits: “Some people with prolonged Covid have stomach symptoms. And the data shows that the virus can persist in the gut, so providing more protection to the lining of the gut can help with that as well.
The nasal vaccine would also be good news for people suffering from needle phobia — a 2021 study by the University of Oxford that questioned 15,000 people suggested that 10 percent of all vaccine hesitancy was related to needle phobia, the magazine reported Psychological Medicine.
“When the news was released [in 2021] that we were working on a nasal vaccine for Covid, we started getting emails from people all over the country asking if they could try it as they don’t like needles,” says Professor Munir. However, there are disadvantages to nasal vaccines. “The one big advantage of injectables is that you know exactly how much is being given,” says Professor Openshaw. With nasal vaccines, you can’t be so sure if some of it was sneezed out or swallowed.
A nasal flu vaccine called Fluenz Tetra is now available to children aged two and three or those with co-morbidities between the ages of two and 17. It contains a live but weakened form of the flu virus. But attempts to develop nasal vaccines that are not based on weakened viruses for other respiratory infections have not yet been successful – a key problem is how to keep the inhaled vaccine in place long enough.
“The nose is lined with mucus and hair-like cells that are good at binding to substances and carrying them back to the stomach – potentially rendering the nasal vaccine useless,” says Professor Openshaw.
There are other obstacles to nasal Covid vaccines. Michael Diamond, a professor of medicine at the University of Washington who helped develop the nasal vaccine approved for use in India, says governments have preferred to fund the development of intramuscular vaccines over others.
“We have a 50-year or more history of administering vaccines by the intramuscular route – we don’t have that experience with these [nasal] vaccines,” he told Good Health.
“The US government gave a lot of support to companies to work with vaccines that they thought were more likely to succeed. This absorbed a lot of resources, so there wasn’t much left to support new initiatives.
After the University of Washington developed…
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