William Petri is Professor of Medicine at the University of Virginia and explains why he thinks a Covid-19 vaccine will be approved soon
Fall is approaching in the Northern Hemisphere and many are wondering if we will finally have a vaccine by January 2021.
I am a medical scientist and specialist in infectious diseases at the University of Virginia, United States. There I treat patients and carry out research on covid-19.
I am occasionally asked how I can be sure that researchers will successfully develop a vaccine to prevent disease, yes not yet we have a for HIV, the virus that causes AIDS.
Below I explain what stage the current investigation is at, where I think we will be in five months and why you can be optimistic that a vaccine against covid-19 will be developed.
1. Our immune system successfully fights covid-19
In 99% of all COVID-19 positive cases, patients recover from the infection and the body clears the virus.
Some of the people who have contracted the disease may remain with low levels of the virus in the body for up to three months after infection.
But in most cases, after 10 days of getting sick, these people can no longer transmit the virus.
For these reasons, it should be much easier develop a vaccine for the new coronavirus than for infections such as HIV, which the immune system cannot cure naturally.
SARS-CoV-2 does not mutate in the same way that HIV does, so it is much easier for the immune system to control or through a vaccine.
2. Antibodies that attack the viral spike prevent infection
A vaccine will protect us, in part, by encouraging the production of antibodies against the viral spike SARS-CoV-2, the virus that causes covid-19
The virus needs the viral spike to stick and enter human cells and reproduce. Researchers have shown that antibodies – such as those produced by the human immune system – bind to the viral spike, neutralize it, and prevent the coronavirus from infecting cells in the laboratory.
Has been shown in clinical trials that vaccines generate antibodies that prevent cells from becoming infected.
At least seven companies have developed monoclonal antibodies – laboratory-made antibodies that detect the viral spike.
These have entered the Phase of clinical trials to test its ability to prevent infection in people who are exposed through household contact, for example.
Monoclonal antibodies can also be effective for treatment. During an infection, a dose of these antibodies could neutralize the virus, giving the immune system a chance to rebuild itself and make its own antibodies to fight the pathogen.
3. Spicule glycoprotein has multiple weak points
Antibodies can bind and neutralize the virus in many places on the viral spike, which is good news because with so many vulnerabilities, it will be difficult for the virus to mutate avoiding the vaccine.
Various parts of the spicule would need to mutate to evade the neutralizing antibodies. Too many mutations in the spike would change its structure and make it unable to bind to the angiotensin II converting enzyme (ACE2), key to infecting human cells.
4. We know how to make a safe vaccine
When researchers understand the possible side effects of the vaccine and how to avoid them, the vaccine becomes safer.
One of the side effects seen in the past was increasing the dependence by the part of the antibodies before an infection. This occurs when the antibodies do not neutralize the virus, but instead allow it to enter cells through a receptor intended for the antibodies.
Researchers have found that when immunized via the viral spike, high levels of neutralizing antibodies are produced, reducing the risk of escalation.
A second potential problem with some vaccines is an allergic reaction It causes inflammation in the lung, as seen in people who received a respiratory syncytial virus vaccine in the 1960s.
This side effect is dangerous because inflammation of the airways in the lungs can make breathing difficult.
However, researchers have now learned to design vaccines that prevent this allergic response.
5. There are several vaccines in development
The United States government is supporting the development of various vaccines through Operation Warp Speed.
The goal of this program is to deliver 300 million doses of a safe and effective vaccine by January 2021.
The US government has invested heavily, committing $ 8 billion to seven different covid-19 vaccines.
By backing multiple vaccines, the government is investing safely. Only one of them needs to be shown to be safe and effective in clinical trials for a Covid-19 vaccine to be available to the American people in 2021.
6. There are already vaccines that have passed phases I and II
Phases I and II test whether a vaccine is safe and induces an immune response.
To date, trials of three different vaccines have yielded results promising and they have managed to trigger the production of levels of neutralizing antibodies at levels two to four times higher than those seen in people who have recovered from COVID-19.
The American Moderna, the British Oxford and the Chinese company CanSino are the three vaccines that have been shown to be safe during phase I and II clinical trials.
7. Phase III clinical trials are already underway
During a phase III trial, the final step of the process, the vaccine is tested in tens of thousands of people to determine if it works and safely prevents SARS-CoV-2 infection.
The vaccine produced by Modern and the US NIH, as well as the Oxford-AstraZeneca Phase III trials began in July.
Other covid-19 vaccines will begin phase III in a few weeks.
8. Acceleration of vaccine production and deployment
Operation Warp Speed has paid for the production of millions of doses of vaccines and supports the manufacture of these on an industrial scale even before researchers have proven their efficacy and how safe they are.
The advantage of this strategy is that once a vaccine is proven safe after phase III clinical trials, there will already be a reservation that can be distributed immediately without compromising the full evaluation of its safety and efficacy.
This is an approach wiser than Russia’s, which is vaccinating the public before proving that the vaccine is safe and effective through phase III.
9. They are already hiring vaccine distributors
McKesson Corp., the largest vaccine distributor in the US, has already been contracted by the Centers for Disease Control and Prevention (CDC) for to distribute the vaccine against covid-19 in the places where the vaccine will be administered, such as hospitals and clinics.
I think it is realistic to say that we will know sometime in late 2020 if some vaccines are safe, how effective they are, and which ones should be used to vaccinate the population in 2021.
* William Petri is Professor of Medicine at the University of Virginia, USA.
* This article was originally published on The Conversation and is reproduced under the Creative Commons license. Click here to read the original article.