Could an inhaled powder vaccine finally offer the chance to end Covid for good?
The vaccine is designed to act in the respiratory tract, where the virus first enters the body. According to a study, the vaccine offers almost instantaneous protection against Covid, compared to conventional injected vaccines, which take up to 14 days to be fully effective.
The inhaled vaccine blocked both infection with the virus and the possibility of transmitting it to other people.
While injected Covid vaccines are very effective at preventing someone from becoming seriously ill and are credited with helping prevent some 14.4 million deaths worldwide since the start of the pandemic, according to the Journal of Paediatrics and Child Health in 2022, are not as effective at stopping mild infections, which can then be transmitted to other people.
Before Christmas, Covid cases began to skyrocket in the UK.
According to a study, the vaccine offers almost instantaneous protection against Covid, compared to conventional injected vaccines, which take up to 14 days to be fully effective.
Around 4.2 per cent of people in England and Scotland tested positive on December 13 (around 2.5 million people), according to figures from the UK Health Security Agency, UKHSA.
And as well as the downside of not being well in the short term, some will develop long Covid.
Therefore, a vaccine that can eliminate the virus before it has a chance to make you sick could have big advantages. An inhaled version could also appeal to those who have a phobia of needles, which makes up around 10 per cent of the population, according to the NHS.
This isn’t the only nasal vaccine in development, so could this really mean the end of Covid as we know it?
So how does the new vaccine work?
The vaccine is made of small spheres that contain the protein unique to the virus that causes Covid. It is inhaled through the nose and absorbed into the blood vessels of the respiratory tract, where immune cells called T cells and B cells (which produce antibodies) attack it and then remember it.
If the real virus then arrives, these immune cells are prepared to attack it quickly.
The results of the study, carried out by researchers at the Chinese Academy of Sciences in Beijing and published in the journal Nature, were carried out in mice, hamsters and monkeys, but trials in humans are now awaited.
Are inhaled vaccines better?
Giving a vaccine as a nasal spray means that there is a greater production of infection-fighting immune cells around the nose and mouth, which are the main entry points for Covid and other respiratory viruses, than would normally be obtained with an injected vaccine.
The vaccine is made of small spheres that contain the protein unique to the virus that causes Covid. It is inhaled through the nose and absorbed into the blood vessels of the respiratory tract, where immune cells called T cells and B cells attack it and then remember it.
The area behind the nose (called the nasopharyngeal area) is lined by a mucous membrane that continues into the intestine and is rich in immune cells, so priming these cells helps stop the virus before it can replicate and move through the body. .
“If a vaccine is inhaled or administered as drops through the nose or mouth, it will prime these cells, which are the first line of defense, to act quickly,” says Professor Muhammad Munir, a virologist at the University of Lancaster.
“A vaccine injected into the muscle, usually the arm, will also produce T and B cells, but these will circulate mainly in the blood and organs,” he adds.
‘Injected vaccines only cause a small amount in the nose and mouth, so they are not ideal protectors for the point where the Covid virus enters.
“It’s like putting security guards behind a wall: With a nasal vaccine, you have those guards where you need them.”
Why do they work faster?
The main benefit is the speed with which antibodies generated in the nasal area will respond once the Covid virus is detected, meaning they will quell the infection before it takes hold.
“These nasal immune cells will act to block the infection within a couple of minutes, while the immune cells produced by the intramuscular vaccine act six to eight hours after the virus enters,” says Professor Munir.
This should mean that the virus is removed before it has a chance to become infected and make someone sick and, more importantly, transmit it to other people.
The latest study follows testing of a nasal vaccine on animals by a team at the University of Maryland, reported in Nature Communications last November, which found it “significantly” reduced Covid infection and transmission.
Around 4.2 per cent of people in England and Scotland tested positive for Covid on December 13 last year (around 2.5 million people), according to figures from the UK Health Security Agency, UKHSA.
Any other advantages?
In addition to appealing to those with needle phobias, the fact that nasal vaccines come in powder form means that, unlike injectables, they don’t need to be kept refrigerated, so they can be easily administered anywhere (a benefit not only here but also in the developing world). .
What’s more, the vaccine presented in the latest Nature study is a single dose, unlike injections, which may require two or three doses.
And the benefits of nasal vaccines may extend beyond Covid.
Peter Openshaw, professor of experimental medicine at Imperial College London, says inhaled vaccines “could have important advantages in preventing (other) infections that enter through the lungs and nose.”
Does that mean I will never get Covid again?
Possibly, but it’s unclear how long protection from a nasal vaccine lasts.
Are standard vaccines not good enough?
Covid injections given into the arms are very good at preventing people from becoming seriously ill.
They have prevented 19.8 million Covid deaths worldwide since their introduction in 2020, according to an article published in The Lancet in June 2022, but they are not as effective at preventing transmission and preventing people from becoming infected as they seem. be the new powder vaccine.
With the standard vaccine shot, protection varies depending on the vaccine and the variant it faces.
According to UKHSA, Moderna’s booster offered an impressive 90 to 95 percent protection against hospitalization from Covid infection nine weeks after vaccination.
When it comes to contracting Covid, it offers 63 percent protection against the BA.1 Omicron variant and 70 percent against BA.2 after two weeks; However, after 25 weeks, that protection fell to 9 percent against BA.1 and 13 percent against BA.2.
What are the drawbacks of nasal vaccines?
They must be administered correctly and there is a chance that someone could sneeze the vaccine before it has taken effect.
“That could happen in theory,” says Andrew Easton, emeritus professor of virology at the University of Warwick.
Experts have expressed concern that the nose is lined with hair-like cells that could propel any vaccine back into the stomach, potentially rendering it useless.
Some also fear that the rapid turnover of mucous membrane cells means that any protection would be short-lived.
However, there appear to be limited side effects. A study published in The Lancet in December involving 30,000 people who received two doses two weeks apart of an intranasal Covid vaccine or a placebo found no serious adverse effects.
How soon could we have a nasal vaccine in the UK?
We already have them. Fluenz Tatra, a nasal vaccine containing a live but weakened form of the flu virus, is given to millions of children each year (but because it contains a live virus, it is not suitable for older people because their immune systems are weaker).
In terms of Covid, there are many nasal vaccines in development around the world, and at least two in the US may be at a stage where they can be presented to regulators later this year.
One of the contenders in the UK, called ViraVac, has been developed by Professor Munir and his team based on a vaccine that was originally sprayed in barns to stop a form of coronavirus in chickens.
This had shown promise in animal studies, but he says he has struggled to find the funding needed to move on to the next stage of research since the World Health Organization downgraded Covid’s status, saying in May last year that ” It was no longer a global problem.” emergency’.
In October 2022, news reports in China showed people receiving the world’s first Covid vaccine that is inhaled through the nose and mouth, which is a version of an injectable vaccine that was used in China as a booster. Its effectiveness is still unclear.
Meanwhile, in January last year, the use of iNCOVACC, a Covid vaccine administered in the form of nasal drops (mainly available in private hospitals) was approved in India as a primary or booster vaccine for those over 18 years of age.