While the Covid-19 pandemic doesn’t appear to be slowing down neither are the scientists working hard on developing vaccines and cures. A new vaccine developed by the University of Oxford has been shown to trigger an immune response in humans.
The first trials for the new vaccine involved 1,077 people and over 90% of them showed positive results. The vaccine triggered the production of both antibodies and T-cells capable of fighting off the novel coronavirus which was the goal. The UK has already ordered 100 million doses of the vaccine provided that further human trials continue to show positive results.
What are T-cells and antibodies?
They are small proteins made by our immune system to specifically stick to the surface of viruses and neutralize them.
Antibodies aren’t “one size fits all”, however, and don’t work against any and all viruses. Our immune systems need to know what kind of virus they are dealing with and what type of antibodies they should build.
That’s precisely the purpose of all vaccines – to “teach” our immune systems what they might have to deal with and help them prepare for it.
This is where T-cells come in. These are a specialized type of white blood cells that help coordinate our immune system and “spot” viruses. Without T-cells, no amount of antibodies can be enough to deal with a virus.
That’s why the production of both T-cells and antibodies is the goal of any vaccine. And both were shown to be effective by this new Oxford vaccine. The T-cell levels of the test subjects were shown to peak ~14 days after vaccination and the levels of antibodies – ~28 days after vaccination.
Professor Andrew Polland from the Oxford research group had this to say about the results “We’re really pleased with the results published today as we’re seeing both neutralizing antibodies and T-cells. They’re extremely promising and we believe the type of response that may be associated with protection. But the key question everyone wants to know is does the vaccine work, does it offer protection… and we’re in a waiting game.”
Of the 1,077 participants, 90% showed production of antibodies and T-cells after just one vaccination, and the others – after a second vaccine.
“We don’t know the level needed for protection, but we can maximize responses with a second dose,” Professor Pollard added.
How was the vaccine made?
The vaccine called ChAdOx1 nCoV-19 was created by genetically re-engineering the virus responsible for the common cold in chimpanzees. The reason it was so suitable for the job is that common cold viruses are also types of coronavirus, different from but similar to Covid-19.
Still, the virus was heavily modified both so it can resemble the novel coronavirus and so it doesn’t cause infections. This was done by transferring the genetic instructions for the virus’s “spike protein” which Covid-19 uses to invade cells into the vaccine. This way, the vaccine “looks like” the novel coronavirus to our immune system and the latter can learn how to fight it.
Are there any side effects?
So far, only mild ones. Around 17% of patients developed a mild fever and over 60% – a headache. There weren’t any other side-effects from the initial trials and all of these were handled easily with paracetamol.
Professor Sarah Gilbert from the Oxford research group said that “There is still much work to be done before we can confirm if our vaccine will help manage the Covid-19 pandemic, but these early results hold promise.”
There are still more trials to be done of course. 1,077 participants may be enough to show promise but are not enough to guarantee neither effectiveness nor safety.
The next stage of the trials is set to include over 10,000 people in the UK. After that, further trials will be expanded to countries outside of the UK with potentially 30,000 participants from the U.S., 5,000 from Brazil, and 2,000 from South Africa.
If treatment options for Covid-19 are discovered in time, there may also be “challenge trials” which include infecting vaccinated people with the coronavirus.
When will the vaccine be available?
As with other in-development vaccines in similar stages, the vaccine may be ready by the end of the year but it still wouldn’t be mass-produced at that point. Health and care workers will be the first to receive any finalized vaccine due to the nature of their work. After that, mass production and distribution to the rest of the population should be available in early 2021 if all goes well.
As UK prime minister Boris Johnson said “Obviously I’m hopeful, I’ve got my fingers crossed, but to say I’m 100% confident we’ll get a vaccine this year, or indeed next year, is, alas, just an exaggeration. We’re not there yet.”
Still, this is amazing progress. As of today, there are 160+ Covid-19 vaccines being developed around the world but only a few of them are going into wider testing. This graph from the World Health Organization (WHO) shows clearly how 140 of those ~160 in-development vaccines are still in pre-trials stages. Oxford’s ChAdOx1 nCoV-19 has joined the “elite” company of just a few vaccines that have so far shown truly promising results.
It should also be pointed out that vaccine research is not a one-winner race. There likely won’t be just the “one best” vaccine for Covid-19 as the virus has already started mutating. Instead, we’ll likely need multiple vaccines for multiple strains of the virus. Or, as Kate Bingham, the chairwoman of the UK Vaccine Taskforce, explained it:
“What we are doing is identifying the most promising vaccines across the different categories, or different types of vaccine, so that we can be sure that we do have a vaccine in case one of those actually proves to be both safe and effective. It’s unlikely to be a single vaccine for everybody. We may well need different vaccines for different groups of people.”