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As fall approaches, many are wondering if the vaccine race will pay off as early as January 2021.
I am a physician scientist and infectious disease specialist at the University of Virginia, where I treat patients and conduct research on COVID-19.
I am sometimes asked how I can be sure that researchers will develop an effective vaccine to prevent COVID-19. After all, we still don’t have one for HIV, the virus that causes AIDS.
Here’s where the current research is, where I think we’ll be in five months, and why you can be optimistic about the delivery of a COVID-19 vaccine.
1. The human immune system cures COVID-19
In as many as 99% of all COVID-19 cases, the patient recovers from the infection and the virus is cleared from the body.
Some of those who have had COVID-19 may have low levels of the virus in the body for up to three months after infection. But in most cases, these people can no longer transmit the virus to other people within 10 days of their first illness.
It should therefore be much easier to make a vaccine against the new coronavirus than for infections like HIV where the immune system fails to cure it naturally. SARS-CoV-2 does not mutate like HIV, making it a much easier target for the immune system to control or for a vaccine to control.
2. Antibodies targeting the spike protein prevent infection
A vaccine will protect, in part, by inducing the production of antibodies against the spike protein on the surface of SARS-CoV-2, the virus that causes COVID-19.
The virus needs the spike protein to attach itself and enter human cells to reproduce. Researchers have shown that antibodies, like those made by the human immune system, bind to the spike protein, neutralize it, and prevent the coronavirus from infecting cells in laboratory culture.
Vaccines in clinical trials have been shown to raise anti-peak antibodies which block viral infection in laboratory cells.
At least seven companies have developed monoclonal antibodies, lab-made antibodies that recognize the spike protein. These antibodies are entering clinical trials to test their ability to prevent infection in those who are exposed, for example, through family contact.
Monoclonal antibodies can also be effective for treatment. During infection, a dose of these monoclonal antibodies could neutralize the virus, giving the immune system a chance to catch up and make its own antibodies to fight the pathogen.
3. Peak Glycoprotein Contains Multiple Targets
The spike protein has many places where antibodies can bind to and neutralize the virus. This is good news because with so many vulnerable points, it will be difficult for the virus to mutate to avoid a vaccine.
Several parts of the tip should mutate to escape the neutralizing anti-tip antibodies. Too many mutations in the spike protein would alter its structure and make it unable to bind to ACE2, which is the key to infecting human cells.
4. We know how to make a safe vaccine
The safety of a new COVID-19 vaccine is improved by researchers understanding the potential side effects of the vaccine and how to avoid them.
A side effect observed in the past was the increase in antibody dependent infection. This happens when the antibodies do not neutralize the virus, but instead allow it to enter cells through a receptor for the antibodies.
The researchers found that by immunizing with the spike protein, high levels of neutralizing antibodies can be produced. This reduces the risk of improvement.
A second potential problem with some vaccines is an allergic reaction that causes inflammation of the lungs, as was seen in people who received a respiratory syncytial virus vaccine in the 1960s.
This is dangerous because inflammation in the air spaces of the lungs can make it difficult to breathe. However, researchers have now learned to design vaccines to avoid this allergic response.
5. Several different vaccines under development
The US government is supporting the development of several different vaccines through Operation Warp Speed.
The goal of Operation Warp Speed is to deliver 300 million doses of a safe and effective vaccine by January 2021.
The US government is making a major investment, committing US $ 8 billion to seven different COVID-19 vaccines.
By supporting several COVID-19 vaccines, the government is hedging its bets. Only one of these vaccines needs to prove safe and effective in clinical trials for a COVID-19 vaccine to be made available to Americans in 2021.
6. Vaccines going through phase I and II trials
Phase I and Phase II trials test whether a vaccine is safe and induces an immune response. Already, the results to date of three different vaccine trials are promising, triggering the production of anti-peak neutralizing antibody levels two to four times higher than those seen in people who have recovered from COVID-19.
Moderna, Oxford and the Chinese company CanSino have all demonstrated the safety of their vaccines in phase I and phase II trials.
7. Phase III clinical trials are underway
In a Phase III trial, the last step in the vaccine development process, the vaccine is tested on tens of thousands of people to determine if it works to prevent SARS-CoV infection. 2 and that it is safe.
The vaccine produced by Moderna and NIH and the vaccine from Oxford-AstraZeneca began phase III trials in July. Other COVID-19 vaccines will begin phase III within a few weeks.
8. Acceleration of vaccine production and deployment
Operation Warp Speed is funding the production of millions of doses of vaccines and supporting the manufacture of vaccines on an industrial scale even before researchers have demonstrated the efficacy and safety of vaccines.
The advantage of this strategy is that once a vaccine is proven safe in phase III trials, a stock of it will already exist and it can be distributed immediately without compromising the full assessment of safety and efficiency.
This is a more cautious approach than that of Russia, which vaccinates the public with a vaccine before it is proven safe and effective in phase III.
9. Vaccine distributors are currently under contract
McKesson Corp., the largest vaccine distributor in the United States, has already been hired by the CDC to distribute a COVID-19 vaccine to sites – including clinics and hospitals – where the vaccine will be administered.
I think it’s realistic for us to know at the end of 2020 whether certain COVID-19 vaccines are safe, exactly how effective they are, and which should be used to immunize the American population in 2021.
William Petri, Professor of Medicine, University of Virginia.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
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