Part II: New Covid-19 Vaccines And Safety Protocols
As I mentioned in my previous post, this is an area that I find really exciting and interesting. But it can be a complicated subject so I’ve broken the information into two posts. This is Part II of my Talk About Vaccines. This second one is about new vaccine types, efforts to create a COVID-19 vaccine and the safety protocols used for testing and approving vaccines. Revisit Part I if you need a refresher on the basics of vaccines.
New Vaccine Technologies
In my previous post, we discussed the classic vaccine technologies that have been used to produce all current vaccines that society utilizes. They are inactivated and attenuated vaccines. However, there are newer methods of vaccination that are currently being researched and have shown promise. This is particularly important as the scientific community races to develop an effective vaccine for COVID-19:
DNA or RNA vaccines: a segment of genetic code from our target virus is injected into the patient, where it will be absorbed by cells, used as instructions to make viral proteins, which are then released into the bloodstream. Since it only encodes for a few proteins and not the whole virus, it’s impossible to start an infection, but it does result in an ever-growing number of foreign proteins in the blood, which causes a strong immune response. DNA vaccines are also easy to manufacture since it is fairly easy to cost-effectively synthesize unique segments of genetic code and clone it into millions of copies. That said, there are risks to address, such as the genetic code accidentally incorporating itself into these cells’s genome, which could negatively impact other functions in hard-to-predict ways. Also, because there would be much more DNA in the bloodstream than normal, there could be a minute risk for these vaccines to trigger an autoimmune response to DNA itself, causing certain forms of lupus or rheumatoid arthritis. While there are some DNA vaccines currently in veterinary use, a DNA vaccine to Covid would be the first such vaccine for human use.
Viral vector vaccines: a harmless virus is genetically engineered to express structural proteins from our target virus. This virus is easily killed off by the immune system, but this lasting immune response also works on the target virus. Viral vector vaccines have proven very effective in clinical trials, working against diseases that originally couldn’t be vaccinated against. The biggest obstacle with viral vector vaccines is that the use of genetic engineering makes them more expensive to produce and requires greater scrutiny for safety, which is a significant hurdle in a pandemic scenario.
Vaccine Safety
The biggest concern second only to efficacy is safety. The US and the global health community has developed a highly effective safety protocol apparatus for testing and approving vaccines. There are multiple stages of vaccine development:
Preclinical testing: the vaccine is developed using animals. Mice or monkeys are given the vaccine to confirm that it works and is safe.
Phase I Clinical trials: the vaccine is given to a small number of people in order to test for safety and dosage. Subjects are given either the vaccine or a placebo, blood samples are taken to see if they’re producing antibodies, and any side effects are noted.
Phase II Clinical trials: the vaccine is given to a group of hundreds of subjects with an emphasis on a diverse range of ages and backgrounds. The methodology is similar to Phase I, but the aim is to confirm that the vaccine is safe for everyone.
Phase III Clinical trials: the vaccine is given to a group of thousands of subjects to test for efficacy. Subjects are given either the vaccine or a placebo and both groups are monitored for a period of time. If few or none from the vaccine group catch the disease while those in the placebo group catch the disease at a normal rate, it shows the vaccine is effective.
Approval: national health agencies examine all the data collected from these trials, confirm these trials were done properly, and decide whether or not to approve the vaccine for use in their country.
Current COVID-19 Vaccine Development
As of now, there are over 140 different vaccines for SARS-CoV-2 in some stage of development by government agencies, research institutes, universities, and private companies around the world. These potential vaccines include examples of all four vaccine technologies we’ve talked about (in Parts I and II of our discussion).
As of the time of writing, there are two vaccines with limited approval; both viral vector vaccines, one made by Chinese company CanSino Biologics working with China’s Academy of Military Medical Science, the other made by Russia’s Ministry of Health. Neither vaccine has had Phase III trials. The Chinese vaccine has only been approved for limited use by Chinese soldiers (an at-risk group) and is currently looking to start Phase III trials. The Russian vaccine was approved without plans for Phase 3 trials, which has been decried by other countries as extremely risky, so it’s unlikely this vaccine will see international approval.
This interactive by the New York Times provides regularly updated information about where the 140 vaccines are in the approval process. Which vaccines will wind up being approved is currently unpredictable. There are now eight undergoing Phase III trials, but how quickly they can perform these trials, whether or not they prove effective, and how quickly they can be approved and by what nations can impact the timeline. As of now, it will likely be autumn or early 2021 before a mass-produced vaccine can be available, though it’s possible for it to take until late 2021 at the latest. So it’s important to continue wearing masks and practicing social distancing until this time comes because it could still be awhile.
The CDC has stated that it will approve any vaccine which can give immunity to 50% of those who receive it. While this might sound too low, this is similar to the efficacy of seasonal flu vaccines (usually between 40 to 60% effective) and is a reasonable goal for a first generation vaccine. Immunizing half of the population against the virus would save millions of lives while also significantly reducing Covid’s ability to spread. Remember, the lower limit of Covid herd immunity is 60% of the population, so such a vaccine would bring us very close to this threshold.
Popular Question
Some are asking how safe will the new Covid-19 vaccine be especially if the timeline for its development and approval is shorter than what is typical. The average vaccine takes 18 months to go through this entire process. It is important that this time is spent in order to confirm that the vaccine works and is safe to take. That said, there are ways to speed up as many parts of the development process without significantly compromising safety. For instance, one major reason why these phases are split up is financial; if a drug fails Phase I clinical trials, you don’t waste money running the other trials. With financial considerations less of a concern with COVID, many vaccine developers are running multiple phase trials at once, such as doing Phase I and Phase II simultaneously. Some nation’s health agencies are willing to approve vaccines for use before they finish all of the trials so long as the data they have is promising enough. And some factories are preparing to manufacture multiple vaccines before final approval, so they can start producing the most effective vaccines the moment approvals are received.
Vaccines in general are safe for the same reason that air travel is safe. Airplanes are by far the safest method of travel in the world today. This sounds counterintuitive (most other vehicles will at least stay in the same spot if they stop working). But because flying is inherently dangerous, planes are over-engineered to prevent failure and pilots need years of training to fly, which contributes to making flying so safe. Likewise, any drug which is meant to be given to an entire population (see my previous posts about herd immunity to understand why) has the potential to be very destructive if they’re at all unsafe. So we have this complex, multi-step process to ensure that each vaccine is safe enough for mass use.
It is important to note that coronaviruses are notoriously hard to develop vaccines for. In fact, SARS-CoV-2 will be the first coronavirus to ever have a successful vaccine. But remember that developing a vaccine for SARS-CoV-2 is probably the biggest area of research in modern human history. This is difficult and it will likely be awhile before we see the results we need to see. But researchers around the world are rising to the occasion. And while our current quarantine measures do have tangible costs in the form of economic decline in the short term, halting the spread and preserving human health and well-being will save lives and improve our economy over the long-term.
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Image Creator: Leigh Prather, Copyright: Leigh Prather
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