Quick Digest and Recent Updates - July 14th 2020: Globally, there are 155 coronavirus vaccines being tested across national institutes, and 23 are currently in human trials. Although vaccines typically take between 10-15 years to create and perfect, scientists and researchers are pushing to get a vaccine out by 2021.
In mid-May, President Trump announced the implementation of Operation Warp Speed (OWS) to accelerate the production and distribution of a COVID-19 vaccine. The goal of OWSÂ is to have 300 million doses of an effective vaccine available by January of 2021. Some of the companies that have received federal funding include Novavax, Moderna, Johnson & Johnson, Merck and Sanofi.
Dr. William Petri, MD, PhD was interviewed for information on the development of a COVID-19 vaccine. Dr. Petri is the Vice Chair for Research of the Department of Medicine and The Chief of Division of Infectious Diseases and International Health at The University of Virginia. He is currently working on the development of a COVID-19 vaccine.
Vaccines generally function by introducing a weakened virus or bacteria into the body to kickstart an immune response. The immune system responds to this virus, or pathogen, by making two types of cells:
Plasma cells produce antibodies, which are able to neutralize the specific virus that caused the infection.
Memory B cells are also produced, which remain dormant in the body. If infected with the virus again, the memory B cells recognize the virus and stimulate an immune response to fight infection.
How long does a vaccine protect me from a disease?
The duration of protection varies by vaccine. Some vaccines, such as the Measles vaccine, leads to lifelong protection in over 99% of cases, while the Pertussis vaccine is effective for about 4-6 years.
Other vaccines, such as the Influenza vaccine may only be effective for a few months. Some people may experience mild side effects from vaccines, such as fevers or rashes. However, these side effects are typically less dangerous than contracting the virus that the vaccine prevents.
What are the types of vaccines?
According to the CDC, there are currently 4 main types of vaccines that are given to young children in the United States. However, the development of the coronavirus vaccine may stray outside of these commonly used approaches.
Live virus vaccines use an attenuated or weakened version of the living bacteria or virus. In a healthy individual, this weakened version of the virus does not typically cause serious illness. However, it is advised that individuals who are immunocompromised consult a health care provider before receiving this type of vaccine. Live virus vaccines typically result in an immune response that lasts many years. Examples include MMR, smallpox, varicella, and yellow fever.
Inactivated virus vaccines use a killed virus or bacteria; however, these vaccines are typically not as long-lasting as the live virus vaccines. Several doses or boosters of inactivated virus vaccines are typically needed to build up immunity. Examples include polio, Flu shot, and Hepatitis A.
Toxoid vaccines target bacteria that produce toxins in the body. These vaccines work by injecting weakened toxins (toxoids) into the body so that the body will produce the proper immune response if infected with a toxin from the disease. An example is the DTaP vaccine, which protects against diphtheria and tetanus.
Subunit vaccines include only the specific parts of the virus that are needed to confer immunity. Therefore, there are fewer side effects and it is safer for immunocompromised individuals to receive these vaccines. Boosters may be needed over time. Examples include hepatitis B, HPV, and shingles.
Phases of Vaccine Testing and Approval
There are several phases a vaccine must go through before being given to the public:
Preclinical testing: The vaccine is given to animals (mice, monkeys) to see if they have any immune response.
Phase I (safety trials): The vaccine is tested by giving it to a small group of people to test the safety and dosage as well as the immune response.
Phase II (expanded trials): The vaccine is tested on several hundred people, including specific groups such as young children or older adults.
Phase III (efficacy trials): The vaccine is given to thousands of people. The rate of infection in this population is compared to a placebo group who does not receive the vaccine. For COVID-19 vaccines, phase III trials will include administering the vaccine to 30,000 people. Since there are currently 5 vaccines that show promise to enter phase III this year, there will likely be 150,000 Americans who get a vaccine as part of phase III.
Approval: Each country has regulators in which they would review the results from the trials and determine whether or not the vaccine is deemed effective and safe. However, during a pandemic, a vaccine may receive emergency approval.
Phase IV: Since it is impossible to know all side effects of a vaccine before it reaches population level, many vaccines undergo studies once they are already on the market. The Vaccine Adverse Event Reporting System studies the vaccines to troubleshoot for problems once the vaccine is on the market.
How Long Until The COVID-19 Vaccine Become Available?
The development of a vaccine is usually a process that takes anywhere from 10 to 15 years. The development of the coronavirus vaccine is highly expedited and the first vaccine should be available within 12-18 months.
The preclinical phase, which includes laboratory and animal studies, typically takes between 3 and 6 years. This expedited process is made possible by the increase in government funding, shortened testing timelines, advances in technology, and previous knowledge of other coronaviruses. Additionally, rather than following the aforementioned testing phases in sequential order, researchers have been granted permission to run multiple phases simultaneously.
For example, the Senior Vice President of Research and Development at Inovio Pharmaceuticals explained that while the phase I trial will be a full year, phase II and III trials will begin before the full year for phase I has elapsed. Even once a vaccine is on the market, it will likely be subject to changes and improvements over the next several years in order to increase its efficacy.
What are the most promising COVID-19 vaccines in-development?
The federal government identified 5 vaccine candidates for the development of the vaccine that seem the most promising in terms of producing a safe and effective vaccine by the winter.
The 5 companies are Moderna, a collaboration between Oxford University and AstraZeneca, Johnson & Johnson, Pfitzer, and Merck. The goal is to have the vaccine ready for the public by the end of this year, or early next year. And if one of these companies are able to do so, it would be setting a record as no vaccine has ever been developed so quickly. The current record for vaccine development is currently only 4 years.
Moderna: Moderna is currently in phase II of clinical trials, where the vaccine is being tested on several hundred people. Moderna’s coronavirus vaccine will likely enter phase III on July 27th. This vaccine is using messenger RNA (mRNA), which has never been used in a vaccine before. Individuals who received this vaccine as part of phase I trials produced more antibodies than someone who was infected naturally with the virus; however, a second injection four week later was necessary. These studies have shown mild side effects, such as pain at the injection site, headache, and chills.
Oxford: The vaccine developed by scientists at Oxford is beginning phase III of clinical trials in Brazil, South Africa and finishing phase II in England. Oxford’s vaccine is based on a common cold virus in chimpanzees (ChAdOx1). This virus has been modified to express a spike protein from the COVID-19 virus.
Johnson & Johnson: The vaccine being developed by Johnson & Johnson is current in preclinical trials. This vaccine is expected to enter phase I and II by the end of July. Johnson & Johnson is using an adenovirus (Ad26) that is being tested in monkeys. The vaccine will soon be tested on over 1,000 middle aged individuals in the United States.
Pfitzer: Pftizer is collaborating with BioNTech and Fosun Pharma to work on a messenger RNA (mRNA) based vaccine. This vaccine is currently in Phase I/II of clinical trials. Individuals who received this vaccine as part of this trial produced antibodies against COVID-19. Individuals experienced mild side effects, such as pain at the injection site and sleep disturbances. They were just granted FDA fast track designation and plan to enter large scale Phase II/III clinical trials in July.
Merck: Merck has recently partnered with IAVI to work on the production of two possible vaccines, one of which would be based on vesicular stomatitis viruses (VSV). This is the same method that was used to produce a vaccine for Ebola. Merck is currently in preclinical trials and hope to create a single dose vaccine.
In addition to these 5 promising vaccines, several other companies have high hopes of producing effective vaccines within the next year.
Different Types of Vaccines
Type of Vaccine
How it Works
Groups Working on These Vaccines
Genetically engineering DNA in the form of a plasmid is injected and makes proteins. The body recognizes these proteins and initiates an immune response.
A virus that has been killed with heat or chemicals is injected. The body initiates an immune response that is usually not as strong as the response to a live virus. Vaccine boosters may be necessary.
Live attenuated virus
A small dose of weakened virus is injected. The body initiates an immune response; however, this may not be suitable for individuals who are immunocompromised.
Codagenix/Serum Institute of India
Non-replicating viral vector
A well-established and deactivated viral vector, such as that of the common cold, is modified to express proteins of the coronavirus. Since the virus of the common cold is missing some of its own genes, it cannot replicate. No approved vaccines of this type currently exist.
Fragments of the virus, rather than the whole virus, is used to elicit an immune response.
WRAIR/USAMRIID, Baylor College of Medicine, Heat Biologics/University of Miami, Novavax
Replicating viral vector
Similar to the non-replicating viral vector vaccines; however, replication of the viral vector produces a strong immune response. Example is the Ebola vaccine.
Institute Pasteur/Themis/University of Pittsburg Center for Vaccine Research
Genetically engineering RNA is injected through the vaccine. No approved vaccines of this type currently exist.
Particles that closely resemble viruses but cannot replicate are injected. This provides a safer alternative to live virus vaccines. Examples include HPV vaccine.
These vaccines do not fall into the other categories. They may include a gene-encoded antibody and other novel approaches.
Herd Immunity: What is it and What Does it Mean in Terms of The End of COVID-19?
Herd immunity is when a large percentage of the population is immune to a disease, making its spread within that population highly unlikely. The entire population does not necessarily need to be immune in order to achieve herd immunity: the percentage of the population that needs to be immune is called the threshold proportion and it depends on the specific virus.
For example, according to the Mayo Clinic, the threshold potential for Influenza is around 60% and 94% for Measles. It is estimated that the threshold potential for COVID-19 is around 70%.
How many people with COVID-19 antibody do we need to have herd immunity?
In order to reach the threshold potential of COVID-19, enough people need to be vaccinated or become naturally infected with the virus. The problem with achieving herd immunity through natural infection is that the antibodies created by means of natural infection may only last several months, potentially leaving people susceptible to reinfection.
Additionally, over 200 million individuals in the U.S. would need to be infected and recover in order to have herd immunity via natural infection. Since the infection of over 200 million people will likely result in many deaths, an economic burden, and overwhelmed hospitals, a vaccine seems to be the most promising way to achieve herd immunity.
Potential Concerns and Questions
Will there be one vaccine or multiple vaccines on the market?
According to Dr. Petri, there will likely be a few vaccines available in the United States in 2021. Over the next few years, however, these vaccines will likely be modified and improved. Modifications will hopefully include increasing the efficacy of the vaccine and increasing the amount of time that the vaccine protects people against the virus.
How long will the vaccine be effective for?
The amount of time the vaccine will be effective for and the frequency of booster vaccines needed to confer immunity is currently unknown. Some methods in developing a vaccine may create immunity for several months, similar to the Influenza vaccine. This type of vaccine would require booster vaccines every few months. Other teams are looking for a way to create long-lasting immunity. Dr. Petri's team is using a similar model to the Yellow Fever vaccine to create a long-lived antibody response.
Will there be side effects to the vaccine?
According to current clinical studies, there have already been some mild side effects noted by researchers. These side effects include body aches, soreness at the point of injection, fever, and sleep disruptions. Dr. Petri explained that rare side effects, however, may not be able to be understood until the vaccine is already on the market. Since some side effects will only affect 1/1,000,000 people, they will likely not be prominent in phase II and III trials, which only include up to 30,000 individuals. The COVID-19 vaccine will likely be under surveillance in phase IV.
Who will get the vaccine first?
The CDC's Advisory Committee on Immunization and The World Health Organization Strategic Advisory Group of Experts on Immunization will make the decisions regarding how to distribute the first vaccines that come to market. In previous cases, individuals such as health care providers, military, older adults, and first responders are usually given priority. Ethicists are currently evaluations which groups of people will benefit most from an early vaccine. Dr. Petri explained that COVID-19 is largely linked to clusters of people, so groups of people in nursing homes, prisons, and healthcare personnel may be a priority.
Will people want to get the vaccine?
Recent research indicates that as few as 50% of people in the United States have indicated that they would be committed to receiving a coronavirus vaccine once available. People are likely worried due to the fast-paced nature of COVID-19 vaccine production. However, once vaccines reach phase III and are tested on 30,000 individuals, public trust of the vaccines may increase. Dr. Petri also noted that it is possible that schools and universities mandate the vaccine once it becomes widely available. This would be following a similar trend as the Meningitis vaccine, which is now required by the College Student Health Association.
Why do we have over 140 groups working on a vaccine?
Over 140 teams are developing a COVID-19 vaccine and have registered with The World Health Organization. Dr. Petri explained that each group working on the COVID-19 vaccine development has unique aspects to offer. The competition of all these teams is actually a good thing, as it will likely result in the most effective vaccine down the line. For example, Dr. Petri's laboratory is working on making their vaccine heat-stable, long-lasting, and resistant against mutations. Additionally, Dr. Petri explains that there unfortunately will be another pandemic down the line. This investment in science, technology, and understanding a vaccine is bound to pay off when we need to come up with new treatments and vaccines for another virus.
What To Do Until the Approval of a Vaccine
There are many good practices you can partake in to help prevent the spread of coronavirus. Different states across the country have various protocols and regulations before completely opening back up in order to ensure the utmost safety for their residents. However, this is a collective effort- so be sure to:
Wear a mask
Wash your hands thoroughly
Practice social distancing
Monitor your symptoms (stay home if you're feeling sick)
Here are some additional resources you might find helpful: