How Are Vaccines Developed?

How Are Vaccines Developed

On November 9, 2020, New York-based pharmaceutical giant Pfizer, announced a new vaccine for COVID-19 that had achieved 90% efficacy. Obviously, this triggered excitement and buzz around the world. The excitement is even greater with an announcement on November 16, that another company, Moderna has developed a vaccine that is 94.5% effective in clinical trials. The announcements are timely as countries the world over begin to report what experts are calling a “third wave’’ of the COVID-19 disease. The data is exciting, but what does it mean? How are vaccines developed?

In the US alone, over 11 million cases of the disease have been reported so far (as of November 16, 2020). The disease has claimed over 1.3 million lives worldwide. Thus a vaccine is more important and welcome than ever. In this post, we’ll provide a brief overview of how vaccines are developed and what this means in light of the recent exciting announcements.

How Are Vaccines Developed?

What is a vaccine?

Vaccines are medications that prepare your immune system to fight infections when your body encounters it a second time. Your immune system, the system in your body that fights off infections, has antibodies.

When you come into contact with a virus or bacteria for the first time, some of these antibodies are made. These antibodies build what is called a “memory” so that the next time the same (or similar) virus or bacteria attacks your body, the antibodies are prepared to fight them off quicker than the first time.

When you receive a vaccine, your body is introduced to either an inactivated/killed, attenuated (this means the disease-causing agent is live but is not able to cause disease) form of the virus or bacteria or you may receive a subunit (a part) of the disease-causing agent.

The new vaccines are mRNA vaccines

Most of the vaccines types described in the paragraph above are traditional vaccines based on original research by Edward Jenner – the person who first showed that immunizing children with cowpox protected them from the deadly smallpox in 1796. Thanks to this foundational work, millions of lives have been saved from other deadly diseases.

The drawback to traditional vaccines however is that they take years – up to 10 years sometimes – to be developed and approved. This involves several steps of testing it in a lab until it can finally be tested in humans and then be approved by the US Food and Drug Administration (FDA).

In order for vaccines to be approved for use, researchers have to show:

1) that it is safe for use in humans so that it does not cause death or serious side effects in otherwise healthy individuals. This is typically done in Phase 1 of clinical trials of a vaccine.

2) that the vaccine is efficient. This means they have to show that the vaccine actually prevents the disease. This is done in Phases 2 and 3 of clinical trials of a vaccine.

For traditional vaccines, this is a long and arduous process that is also very expensive. A newer type of vaccine, the mRNA vaccine, circumvents these drawbacks. They are quicker to develop and produce.

The quick development, however, does not decrease how powerful these vaccines are. In fact, so far, other mRNA vaccines that have been developed for other conditions seem to be safer than traditional vaccines. Both the Pfizer and Moderna vaccines are mRNA-based vaccines.

The studies

In the Pfizer study, the researchers evaluated a 2-dose treatment (separated by 21 days) with the vaccine at different doses. The Phase 3 clinical trial of the vaccine started on July 27 2020 and enrolled 43,538 subjects into the study. Of this number, 38,955 have received a second dose of the vaccine.

The researchers hope to follow-up with the subjects for up to 26 months. When these studies are conducted, half of the subjects are placed into the control group that does not receive the vaccine or gets a placebo, and while the other half receives a vaccine.

After almost two months of data, researchers showed that 94 out of the total 43,538 subjects who had confirmed COVID-19 infections. They did not however share whether these individuals were in the control group or the group that received the vaccine.

But according to the information they released, this data represents a 90% efficacy in protecting people from SARS-COV-2. In the Moderna study, there were 30,000 participants. Half received a placebo while the other half were vaccinated.

This was also a two-dose vaccine trial that was separated by 28 days. Only 5 individuals in the vaccinated group had confirmed COVID-19 infections whereas there were 90 in the placebo control group.

Moderna’s early data showed a 94.5% efficacy for the vaccine.

When will the vaccine become available?

There are no licensed vaccines or medications to prevent and/or treat COVID-19. This makes these announcements especially exciting.

Which prompts the question: “When can people start getting the vaccine?” As mentioned above, these are all early data. In Pfizer’s case, they plan to follow the people who received the vaccine for 26 months.

So, there is still a lot of data to come. There are still a lot of unanswered questions.

However, based on the emergency nature of COVID-19, the FDA activated the Emergency Use Authorization which means that after two months of researchers showing the potential safety and efficacy of the vaccine, companies could submit the vaccine for approval.

The Pfizer vaccine will reach that milestone in the third week of November 2020. According to Moderna, they will file their submission for approval “in coming weeks”.

After that, it depends on how long the FDA’s experts, as well as independent experts, take to review the information and approve the vaccine. Thus, while it is not clear when exactly the vaccine will become available to everyone, it appears closer than ever.

Based on current projections, Pfizer expects to produce up to 50 million vaccine doses in 2020 and up to 1.3 billion in 2021.