A SINGLE-SHOT VACCINE THAT PROTECTS AGAINST MULTIPLE STRAINS MIGHT BE AVAILABLE IN 5 YEARS

FILE PHOTO: The word "COVID-19" is reflected in a drop on a syringe needle in this illustration taken November 9, 2020. REUTERS/Dado Ruvic/Illustration

Preventing Another Pandemic – A Single Vaccine That Can Protect Against Multiple Coronavirus In 5 Years

In 2017, scientists and researchers wanted to develop a single vaccine against all types of Coronavirus. However, the ambitious proposal was given a low priority at the National Institute of Allergy and Infectious Diseases (NIAID). That’s because at the time, no one had proven a vaccine could stop even a single beta Coronavirus – the notorious viral group linked to SARS and MERS.

Fast-forward 2021 and the world saw nearly 3 million deaths in April, only to jump to 4 million death toll this month. The novel Coronavirus SARS-CoV-2 (aka 2019-nCoV), the virus that causes the illness Covid-19, has made NIAID and other funders interested again. The pandemic has also attracted the attention of CEPI (Coalition for Epidemic Preparedness Innovations).

In March, CEPI, an international non-profit co-founder in 2017 by the Bill and Melinda Gates Foundation, announced it would invest up to US$200 million in a new program to accelerate the creation of vaccines against beta Coronaviruses, a family that now includes Covid-19. A call for proposals was launched to develop broadly protective SARS-CoV-2 vaccines and Betacoronavirus vaccines.

The threat of another Coronavirus pandemic, perhaps in the next 10 years or 50 years, now seems very real. Besides bats, Coronaviruses infect camels, birds, cats, horses, pigs, rabbits, pangolins, and other animals from which they could jump into human populations. It’s foolish to think the next Coronavirus will happen in another 100 years, as in the case of Spanish flu in 1918.

CEPI’s call to develop broadly protective Coronavirus vaccines forms part of its long-term US$3.5 billion investment strategy. While the world has developed vaccines against the Coronavirus that causes Covid-19, Variants of Concern (VOC) such as United Kingdom “Alpha” variant (B.117), South African “Beta” variant (B.1.351), and Indian “Delta” variant (B.1.617.1) now poses a new threat.

Besides their ability to spread rapidly, the variants can reinfect people who have been infected before, rendering existing vaccines less effective. The increased transmissibility (Delta is 40-60% more transmissible than Alpha, which itself is 50% more transmissible than the most common Covid-19 strain) of these variants could result in a reversal in the global downward trends in transmission.

While the CDC (Centers for Disease Control and Prevention) says that fully vaccinated people don’t need a Covid-19 booster shot at this time, it’s possible that could change in the future. The priority now is to get as many people vaccinated as possible with the current vaccines, both to protect them from disease and to reduce the possibility of the emergence of new variants.

The problem with the current vaccines is that they were designed to protect against one particular Coronavirus – SARS-CoV-2.  What if the Coronavirus responsible for SARS and MERS suddenly spread in the near future?  The SARS and MERS Coronaviruses are deadlier as they were associated with case fatality rates of 10%-35% (5-16 times worse than Covid-19).

In May, a team of scientists and researchers at the Duke Human Vaccine Institute (DHVI) has developed a new vaccine – called a “pan-coronavirus” vaccine – that is proven effective in protecting monkeys and mice from a variety of Coronavirus infections, including SARS-CoV-2 as well as the original SARS-CoV-1 and related bat Coronaviruses that could potentially cause the next pandemic.

Barton F. Haynes, M.D., senior author and director of the Duke Human Vaccine Institute, said – “We began this work last spring with the understanding that, like all viruses, mutations would occur in the SARS-CoV-2 virus, which causes Covid-19. The mRNA vaccines were already under development, so we were looking for ways to sustain their efficacy once those variants appeared.”

“This approach not only provided protection against SARS-CoV-2, but the antibodies induced by the vaccine also neutralized variants of concern that originated in the United Kingdom, South Africa and Brazil. And the induced antibodies reacted with quite a large panel of Coronaviruses.” – said Haynes, who built on earlier studies involving SARS with his colleagues.

Apparently, the scientists found that a person who had been infected with SARS developed antibodies capable of neutralizing multiple Coronaviruses – suggesting that a pan-coronavirus might be possible. The vulnerability for the Coronaviruses is their receptor-binding domain, located on the spike that links the viruses to receptors in human cells.

While this binding site allows the virus to enter the body and cause infection, it can also be targeted by antibodies. It’s this Achilles heel that scientists were targeting by designing a nanoparticle vaccine to block Covid virus. In tests of its effect on monkeys, the nanoparticle vaccine successfully blocked Covid-19 infection by 100%. 

The researchers of DHVI now hope to start enrolling people in clinical trials as quickly as possible – between 18 months and 2½ years from now. But DHVI isn’t the only institute that is developing a single vaccine to protect us against multiple Coronaviruses. Some two dozen other research groups around the world have similar pan-coronavirus vaccine projects underway.

While no pan-coronavirus vaccine has entered human trials so far, the success of vaccines against current Covid-19 (SARS-CoV-2) has sparked optimism. NIAID’s Barney Graham, who helped develop Moderna’s mRNA COVID-19 vaccine, expressed his optimism about pan-coronavirus vaccines – “Compared to the flu and HIV, this is going to be relatively easy to accomplish.”

Generally, an ideal pan-coronavirus vaccine would protect people from all four of its strains – Alpha, Beta, Gamma, and Delta. Researchers at the Duke Human Vaccine Institute also found out that the pan-coronavirus vaccine is stronger or more effective than mRNA vaccines developed by Pfizer and Moderna against South African “Beta” variant (B.1.351).

Unlike the seasonal flu (a descendant of the 1918 Spanish flu pandemic), of which we still do not have a 100% effective vaccine because influenza viruses mutate very quickly, a pan-coronavirus vaccine would not be a seasonal vaccination. Once you have received the pan-coronavirus vaccine, you don’t have to go back for new doses, as long as protective immunity stayed above a certain level.

In fact, CEPI wanted to create “libraries” of vaccines parked around the world at strategic locations so that when an outbreak happens, those vaccines can be used immediately. However, it’s easier said than done. The Coronavirus family was so large that in the past 10 years, the NIAID has identified hundreds of new Coronaviruses.

Kirsty Le Doare, professor of Vaccinology and Immunology at Imperial College London, said it would take 5 to 10 years of continued investment to develop the ambitious broadly protective-coronavirus vaccines. So far, CEPI has already invested US$33 million in US-based biotech VBI Vaccines and US$170 million in South Korea’s SK bioscience to develop a single shot that protects against multiple Covid-19 variants.

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