What’s The Difference Between Covid-19 Coronavirus Vaccines

Coronavirus COVID-19 single dose small vials and multi dose in scientist hands concept. Research for new novel corona virus immunization drug.

The world can’t return to normal without safe and effective vaccines against the SARS-CoV-2 coronavirus along with a coordinated global vaccination programme.

Researchers have been racing to develop potential drugs that could help end the ongoing Covid-19 pandemic. There are currently around 200 vaccine candidates and about a quarter passed preclinical tests and are now undergoing clinical trials.

What’s the difference between the various candidate vaccines?

A pie chart of candidates can be cut several ways. One is to slice it into six uneven pieces according to the technology (or ‘platform’) that’s used to produce the drug. Those six technologies can be grouped into three broader categories: dead or disabled viruses, artificial vectors, and viral components.

Dead or disabled viruses

Traditional vaccines contain a dead or disabled virus, designed to be incapable of causing severe disease while also provoking an immune response that provides protection against the live virus.

1. Live-attenuated viruses

Attenuated means ‘weakened’. Weakening a live virus typically involves reducing its virulence — capacity to cause disease — or ability to replicate through genetic engineering. The virus still infects cells and causes mild symptoms.

For a live-attenuated virus, an obvious safety concern is that the virus might gain genetic changes that enable it to revert back to the more virulent strain. Another worry is that a mistake during manufacturing could produce a defective vaccine and cause a disease outbreak, which once happened with a polio vaccine. MORE FOR YOUJapan Has Opened Hayabusa2’s Capsule, Confirming It Contains Samples From Asteroid RyuguDonald Trump’s Presidency Will End On The Day Of A Comet, A Meteor Shower And A Total Eclipse Of The SunIn A New Epidemiological Study, Daily Doses Of Glucosamine/Chondroitin Are Linked To Lower All-Cause Mortality

But using a live-attenuated virus has one huge benefit: vaccination resembles natural infection, which usually leads to robust immune responses and a memory of the virus’ antigens that can last for many years.

Live-attenuated vaccines based on SARS-CoV-2 are still undergoing preclinical testing, developed by start-up Codagenix and the Serum Institute of India.

2. Inactivated viruses

Inactivated means ‘dead’ (‘inactivated’ is used because some scientists don’t consider viruses to be alive). The virus will be the one you want to create a vaccine against, such as SARS-CoV-2, which is usually killed with chemicals.

Two Chinese firms have developed vaccines that are being tested for safety and effectiveness in large-scale Phase III clinical trials: ‘CoronaVac’ (previously ‘PiCoVacc’) from Sinovac Biotech and ‘New Crown COVID-19’ from Sinopharm. Both drugs contain inactivated virus, didn’t cause serious adverse side-effects and prompted the immune system to produce antibodies against SARS-CoV-2.

Sinopharm’s experimental vaccine has reportedly been administered to hundreds of thousands of people in China, and both drugs are now being trialled in countries across Asia, South America and the Middle East.

COVID-19 vaccine landscape (left) and platforms for SARS-CoV-2 vaccine development (right)
The global COVID-19 vaccine landscape (left) and Vaccine platforms used for SARS-CoV-2 vaccine … [+] Springer

Artificial vectors

Another conventional approach in vaccine design is to artificially create a vehicle or ‘vector’ that can deliver specific parts of a virus to the adaptive immune system, which then learns to target those parts and provides protection.

That immunity is achieved by exposing your body to a molecule that prompts the system to generate antibodies, an antigen, which becomes the target of an immune response. SARS-CoV-2 vaccines aim to target the spike protein on the surface of coronavirus particles — the proteins that allows the virus to invade a cell.

3. Recombinant viruses

A recombinant virus is a vector that combines the target antigen from one virus with the ‘backbone’ from another — unrelated — virus. For SARS-CoV-2, the most common strategy is to put coronavirus spike proteins on an adenovirus backbone.

Recombinant viruses are a double-edged sword: they behave like live-attenuated viruses, so a recombinant vaccine comes with the potential benefits of provoking a robust response from the immune system but also potential costs from causing an artificial infection that might lead to severe symptoms.

A recombinant vaccine might not provoke an adequate immune response in people who have previously been exposed to adenoviruses that infect humans (some cause the common cold), which includes one candidate developed by CanSino Biologics in China and ‘Sputnik V’ from Russia’s Gamaleya National Research Centre — both of which are in Phase III clinical trials and are licensed for use in the military.

To maximize the chance of provoking immune responses, some vaccines are built upon viruses from other species, so humans will have no pre-existing immunity. The most high-profile candidate is ‘AZD1222’, better known as ‘ChAdOx1 nCoV-19’ or simply ‘the Oxford vaccine’ because it was designed by scientists at Oxford University, which will be manufactured by AstraZeneca. AZD1222 is based on a chimpanzee adenovirus and seems to be 70% effective at preventing Covid-19.

Some recombinant viruses can replicate in cells, others cannot — known as being ‘replication-competent’ or ‘replication-incompetent’. One vaccine candidate that contains a replicating virus, developed by pharmaceutical giant Merck, is based on Vesicular Stomatitis Virus (VSV), which infects guinea pigs and other pets.

4. Virus-like particles

A virus-like particle, or VLP, is a structure assembled from viral proteins. It resembles a virus but doesn’t contain the genetic material that would allow the VLP to replicate. For SARS-CoV-2, the VLP obviously includes the spike protein.

One coronavirus-like particle (Co-VLP) vaccine from Medicago has passed Phase I trials to test it’s safe and has entered Phase II to test that it’s effective.

While there are currently few VLPs being developed for Covid-19, the technology is well-established and has been used to produce commercial vaccines against human papillomavirus (HPV) and hepatitis B.

Viral components

All vaccines are ultimately designed to expose the immune system to parts of a virus, not the whole thing, so why not deliver just those parts? That’s the reasoning behind vaccines that only contain spike proteins or spike genes.

5. Proteins

Protein-based vaccines can consist of the full-length spike protein or the key part, the tip of the spike that binds the ACE2 receptor on the surface of a cell — ACE2 is the lock that a coronavirus picks in order to break into the cell.

Manufacturing vaccines containing the protein alone has a practical advantage: researchers don’t have to deal with live coronaviruses, which should be grown inside cells within a biosafety level-3 lab.

A vaccine against only part of the protein — a ‘subunit’ — will be more vulnerable to being rendered useless if random mutations alter the protein, known as ‘antigenic drift‘, but full-length proteins are harder to manufacture. The immune system can recognize either as an antigen.

One candidate vaccine based on protein subunits is ‘NVX-CoV2373’ from Novavax, where the spike subunits are arranged as a rosette structure. It’s similar to a vaccine that’s already been licensed for use, FluBlok, which contains rosettes of protein subunits from the influenza virus.

6. Nucleic acids

Nucleic-acid vaccines contain genetic material, either deoxyribonucleic acid or ribonucleic acid — DNA or RNA. In a coronavirus vaccine, the DNA or RNA carries genetic instructions for producing a spike protein, which is made within cells.

Those spike genes can be carried on rings of DNA called ‘plasmids’, which are easy to manufacture by growing them in bacteria. DNA provokes a relatively weak immune response, however, and can’t simply be injected inside the body — the vaccine must be administered using a special device to force DNA into cells. Four DNA-based candidates are in Phase I or II trials.

The two most famous nucleic-acid vaccines are the drugs being developed by pharmaceutical giant Pfizer, partnered with BioNTech, and Moderna. Pfizer’s ‘BNT162b2’ and Moderna’s ‘mRNA-1273’ both use ‘messenger RNA’ — mRNA — to carry the spike genes and are delivered into cells via a lipid nanoparticle (LNP). The two mRNA vaccines have completed Phase III trials and preliminary results suggests they’re over 90% effective at preventing Covid-19.

As the above examples show, not only there are many potential vaccines but also various approaches. And while some technologies have already provided promising results, it remains to be seen which will actually be able to defeat the virus.

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JV Chamary

JV Chamary

I’m a science communicator specialising in public engagement and outreach through entertainment, focusing on popular culture. I have a PhD in evolutionary biology and…

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TODAY

Dr. Ashish Jha, dean of Brown University’s School of Public Health, joins the 3rd hour of TODAY to break down the differences between Moderna’s and Pfizer’s coronavirus vaccine candidates. He also comments on speculation of another national shutdown and whether families should still get together over Thanksgiving. » Subscribe to TODAY: http://on.today.com/SubscribeToTODAY » Watch the latest from TODAY: http://bit.ly/LatestTODAY About: TODAY brings you the latest headlines and expert tips on money, health and parenting. We wake up every morning to give you and your family all you need to start your day. If it matters to you, it matters to us. We are in the people business. Subscribe to our channel for exclusive TODAY archival footage & our original web series. Connect with TODAY Online! Visit TODAY’s Website: http://on.today.com/ReadTODAY Find TODAY on Facebook: http://on.today.com/LikeTODAY Follow TODAY on Twitter: http://on.today.com/FollowTODAY Follow TODAY on Instagram: http://on.today.com/InstaTODAY Follow TODAY on Pinterest: http://on.today.com/PinTODAY#COVID19Vaccines#AshishJha#TodayShow

Covid Vaccine Frontrunner Moderna Says Vaccine Won’t Be Approved Until Spring 2021

Pharmaceutical company Moderna, one of the companies in the lead pack in the race to develop a coronavirus vaccine, won’t be in a position to widely distribute it until at least next spring, CEO Stéphane Bancel told the Financial Times, echoing public health experts who predict a similar timeline for other vaccine candidates.

Key Facts

“November 25 is the time we will have enough safety data to be able to put into an emergency use authorization file that we would send to the FDA,” Bancel said, adding that an approval wouldn’t be expected until late first quarter or early second quarter of 2021.

The timeline matches up with what public health experts have previously laid out, which is that a vaccine could be found to be safe and effective by the end of the year at the earliest but widespread distribution wouldn’t occur until further into 2021.

One of the frontrunners to develop a safe vaccine first, Moderna earlier in the month said it was slowing its trial enrollment to ensure it was representing disproportionately affected minority groups but later added it could have enough data by November to know if its vaccine candidate works.

The comments follow Trump’s claim during Tuesday’s U.S. presidential debate that, “We’re weeks away from a vaccine,” citing Moderna as well as Pfizer and Johnson & Johnson.

Pfizer is another frontrunner—Johnson & Johnson are further behind their late-stage clinical trials—and while its CEO Albert Bourla said it will have an “answer” by the end of October on its candidate’s efficacy, a spokesperson for the company later told the New York Times that Pfizer wouldn’t be close to the completion of its clinical trial by then.

There are currently 11 vaccines in expansive Phase 3 clinical trials, according to data from the Times.

Chief Critic

Trump has pushed the notion that a vaccine will be ready before the November election, fueling fear in the U.S. that anything approved could have been rushed. Even with wide distribution of a vaccine, the upwards of 60% to 70% will need to be immunized to put an end to the pandemic. That could take until 2022, according to billionaire and philanthropist Bill Gates and Dr. Soumya Swaminathan, the World Health Organization’s chief science officer.

Key Background

A Covid-19 vaccine is being developed at an unprecedented speed, with a typical immunization taking 10 years to develop, test, approve and distribute. The U.S. leads the world in confirmed cases of the coronavirus with 7,221,278, as well as reported deaths with 206,693. In total, there are 33,802,841 global infections and 1,010,477 deaths.

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Matt Perez

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I cover breaking news and also report on the video game industry. I previously wrote for sites like IGN, Polygon, Red Bull eSports, Kill Screen, Playboy and PC Gamer. I also managed a YouTube gaming channel under the name strummerdood. I graduated with a BA in journalism from Rowan University and interned at Philadelphia Magazine. You can follow me on Twitter @mattryanperez.

Scientists Raise Questions About Moderna Vaccine In Market-Shaking Report

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Vaccine experts expressed skepticism about the Covid-19 vaccine trial results announced by biotech company Moderna on Monday, telling the medical publication Stat News that the company has yet to release significant data to support its claim that its drug successfully produced antibodies in human trials.

KEY FACTS

On Monday Moderna announced in a press release that “positive” data was collected from an early-stage human trial of a coronavirus vaccine, sending its stock valuation and the Dow Jones surging.

But two vaccine experts interviewed by Stat noted that Moderna has yet to publish its studies in scientific journals, and pointed out that the company disclosed results from only eight of the 45 subjects, meaning the majority of the outcomes remains unknown.

The Stat report sent the Dow Jones Industrial Average tumbling in its final hour of trading Tuesday afternoon as skepticism over the vaccine’s readiness hit the market.

The experts also noted the silence from the National Institute for Allergy and Infectious Disease, Moderna’s partner in developing the vaccine, which declined to comment on the Cambridge, Massachusetts-based company’s Monday announcement, which is abnormal for the institute that usually tauts its success, according to Stat.

“When a company like Moderna with such incredibly vast resources says they have generated SARS-2 neutralizing antibodies in a human trial, I would really like to see numbers from whatever assay they are using,” John “Jack” Rose, a vaccine researcher from Yale University, told Stat.

It remains unclear whether the Covid-19 antibodies produced by the body as a result of vaccination are as good as antibodies produced by the body from surviving coronavirus.

When Stat asked Moderna about this, they said antibody level information “will be disclosed in an eventual journal article from NIAID.”

Chief Critic

“It’s a bit of a concern that they haven’t published the results of any of their ongoing trials that they mention in their press release. They have not published any of that,” Johns Hopkins University vaccine researcher Anna Durbin told Stat.

Key Background

On Monday, Moderna announced “positive” results from an early-stage human trial of their preventative COVID-19 vaccine, driving stock market gains, which boosted Moderna’s market cap to a $29 billion valuation—without a single product on the market— according to Stat.

Moderna is expected to launch a phase 2 trial of the vaccine in the coming weeks, with phase three expected to occur in July. Moderna has yet to mention when the vaccine will be available to consumers. Though the company received $500 million in federal cash to bring the vaccine to market, and do so fast, according to Forbes. And the new co-chair of the White House vaccine project is Moncef Slaoui, a former Moderna executive, who reportedly divested his $12.4 million in Moderna stock options on Monday.

Moderna’s vaccine works by using mRNA (“messenger RNA”) that when injected, signals the body to produce Covid-19 antibodies without actually making the person sick from Covid-19. But there are over 100 other companies working to develop a coronavirus vaccine, with eight (including Moderna) at the human trial phase, according to the World Health Organization.

Further Reading

Vaccine experts say Moderna didn’t produce data critical to assessing Covid-19 vaccine (Stat)

Moderna Reveals ‘Positive’ Data In Coronavirus Vaccine Trial, Markets Spike (Forbes)

FDA ‘Fast Tracks’ First Coronavirus Vaccine From Moderna (Forbes)

Fueled By $500 Million In Federal Cash, Moderna Races To Make A Billion Doses Of An Unproven Cure (Forbes)

Full coverage and live updates on the Coronavirus

Send me a secure tip.

I’m the Under 30 Editorial Community Lead at Forbes. Previously, I directed marketing at a mobile app startup. I’ve also worked at The New York Times and New York Observer. I attended the University of Pennsylvania where I studied English and creative writing. Follow me on Instagram and Twitter at @iamsternlicht.

Source: https://www.forbes.com

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The results of one small study on a possible coronavirus vaccine with humans are in, and they appear to show encouraging results. Reporting for TODAY, NBC News medical correspondent Dr. John Torres says “we’re keeping our fingers crossed.” » Subscribe to TODAY: http://on.today.com/SubscribeToTODAY » Watch the latest from TODAY: http://bit.ly/LatestTODAY About: TODAY brings you the latest headlines and expert tips on money, health and parenting. We wake up every morning to give you and your family all you need to start your day. If it matters to you, it matters to us. We are in the people business. Subscribe to our channel for exclusive TODAY archival footage & our original web series. Connect with TODAY Online! Visit TODAY’s Website: http://on.today.com/ReadTODAY Find TODAY on Facebook: http://on.today.com/LikeTODAY Follow TODAY on Twitter: http://on.today.com/FollowTODAY Follow TODAY on Instagram: http://on.today.com/InstaTODAY Follow TODAY on Pinterest: http://on.today.com/PinTODAY #Vaccine #Coronavirus #TodayShow
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