(Editor’s note: This column was written before Pfizer began shipping the vaccine on Dec. 14.)
The purpose of this column is to briefly describe the process vaccines must go through to prove they are safe and effective. I also want to emphasize how important vaccination will be to end this pandemic. There must be widespread vaccination for our society to return back to normal. We are now in the middle of the biggest public health crisis since 1918. The entire healthcare system and especially prehospital providers have been under great strain. The only way to end the pandemic is by vaccination. The process of vaccine development and administration has a long and proven track record of safety in our country. Vaccine development and administration is something that the United States is very good at.
In the United States vaccines must go through a thorough process to prove that they are safe and effective. This is a multi-step process which is monitored for safety throughout. At the end of this process the Food and Drug Administration reviews all the data before giving approval for the vaccine to be given to the public. Each vaccine candidate must go through several phases of trials which are numbered sequentially One through Three.
As mentioned above, a vaccine candidate vaccine must go through an approval process which involves three different phases. Each phase is larger and more complex than the phase before it. Phase One trials typically have 30-50 participants. They are meant to determine if the vaccine generates an immune response and if there are any initial safety concerns. They are also meant to help determine the best dosing. Phase Two trials are larger and have hundreds of participants. Their purpose is to assess safety and determine how much of an immune response is generated by the vaccine. Phase Three trials include the largest number of participants. They normally include tens of thousands of participants. A phase three trial is meant to determine how well the vaccine protects people from the disease and also looks for more rare adverse reactions. Phase Three trials follow patients for several months. The full multi-phase process is important in insuring that we have a safe and effective vaccine.
The United States has not permitted any shortcuts in the development of a COVID vaccine. Some countries have cleared vaccines for deployment to the general population without undergoing the final phase Three trials. This is not the case in the United States. In the U.S., vaccines have to go through the full three phase process. This is very important. Phase three testing with 30,000 or more subjects ensures that we will have a safe and effective vaccine. By requiring a phase three trial the FDA is ensuring that we will have a safe and effective vaccine. Both of the vaccine candidates being considered for approval by the FDA at this time have undergone phase three testing. At this time there are two candidate vaccines going to the FDA for possible approval. These vaccines are being developed by Pfizer and Moderna respectively. The data for these vaccine trials is very encouraging.
The Pfizer vaccine started phase three testing on July 17 and final data was ready on November 18th. There were 43,000 participants in the Pfizer phase three trial. There were 162 cases of COVID in the placebo group and eight cases in the group which received the vaccine. None of the cases in the group which received the vaccine were severe. The main adverse events reported were fatigue in 3.8 percent of people who received the vaccine and headache in two percent. The biggest challenge with the Pfizer vaccine will be that it must be stored and transported at negative 94 degrees Fahrenheit.
The Moderna vaccine started phase three testing on July 17th. Preliminary data was analyzed on November 16th and final data was ready on November 30th. There were more than 30,000 participants at 100 clinical sites. In all there were 196 patients in the study who got COVID-19. Of the subjects that got COVID, 185 were in the placebo group. There were 11 cases of COVID in the group which received the vaccine. Of the 11 people in the vaccine group who contracted COVID none had severe symptoms. There were no serious adverse reactions in the group which received the vaccine. The main adverse events noted included injection site pain, fatigue, muscle aches, joint pains, headache and redness at the injection sites.
We will have safe and effective vaccines for COVID. The only way to end the pandemic is for greater than 70 percent of the population to get vaccinated. We must get our society back to normal. We must also protect ourselves and our patients from COVID. We are lucky that we have a very robust healthcare system in this country which can rapidly develop safe and effective vaccines. Candidate vaccines are undergoing a rigorous multi-phase process to insure they are safe and effective. If the FDA reviews the final data and gives approval then I trust that we will have safe and effective vaccines which will allow our society to heal and get back to normal.