If you were asked to describe 2020 in just a few words, ‘COVID-19’ and ‘vaccine’ would probably be among them. As information about the virus has been circulating, so have concerns regarding the safety and efficacy of possible vaccines against it—particularly over the rapid rate at which these potential vaccines appear to have been designed, created and tested.
In part 1 of this series, we examined the composition of various vaccines and their effects on the immune system. Here we’ll take a closer look at how vaccines are designed, produced and tested.
Vaccines are produced in a variety of ways depending on the pathogen that they are designed to work against and the final form the vaccine will take. The vaccine production process is complex, involving many different steps from initial analysis and design, through clinical development and testing, and on to mass production, administration and the achievement of herd immunity.
The design process begins with a thorough analysis of the pathogen at both the molecular and macroscopic levels. What type of microorganism is it (e.g. a virus or bacteria)? What parts of the body does it target (e.g. the respiratory system or nervous system)? How does it affect and interact with the human body? What are its mechanisms of action? Does it lay dormant in the body? Does it secrete a toxin, or does it act by hijacking the body’s cells? How infectious is it? What are the most common routes of transmission?
This intimate knowledge of how the pathogen operates, how it’s transmitted, and how it behaves is essential to developing an effective vaccine. Most importantly, it guides the selection of an appropriate antigen. We took a close look at antigens in part 1 of this series, where we explained that antigens are the ‘active ingredients’ in vaccines and consist of small particles derived from the pathogen that the vaccine is designed to work against.
Any antigen that is selected must be stable over time, be sufficiently immunogenic, invoke a protective immune response and be suitable for commercial and mass production.
Once analysis and design stage is complete, the candidate vaccine must pass through a series of clinical trials in which it is rigorously tested for immunogenicity, safety and efficacy. The final stages of vaccine development and production include regulatory approval, manufacturing and ongoing quality control and monitoring.
After the vaccine has been designed, produced, and successfully tested on cells (in-vitro), and in animal trials (in-vivo), it proceeds to the clinical development stage. This typically involves a three-phase trial process, often with a fourth phase to cover quality control and regulatory approval.
During the first phase of clinical trials, small groups of people receive the trial vaccine. They are usually healthy recipients with no known comorbidities (conflicting pre-existing illnesses or conditions).
In this phase, the vaccine is administered to a larger group of people, often with specific characteristics (such as age and physical health) similar to those for whom the new vaccine is intended.
At this stage, the vaccine is tested for efficacy and safety and will be administered to a much larger group of participants (typically thousands of people).
Not strictly part of the clinical trial process, this phase involves the formal, ongoing studies and monitoring after the vaccine has been approved, licensed and routinely administered to the community.
Concerns have been raised regarding the manufacture of vaccines with one of the biggest controversies being the use of cells from aborted foetuses. It is true that some vaccines are produced this way. However, it’s important to note that this is not done by repeated abortions. Rather, the cells used were sourced many decades ago from surgically aborted foetuses and have subsequently propagated in laboratories. These cells have become ‘cell lines’ that have been replicated globally many times over. They have allowed researchers and pharma companies to develop and manufacture vaccines against many deadly diseases. Some of the most notable cell lines used for this purpose are WI-38 and MRC-5, both originating from the 1960s.
Animal and human testing are also areas of ethical dilemma. As we mentioned earlier, vaccines must pass through a series of animal and human trials to ensure they are safe to administer. Each of the steps of these trials must be approved by an independent ethics committee before it can proceed, and many measures are put in place to minimise the harm and risks to any animal or human participants wherever possible.
Although relatively rare, some members of the community may have adverse reactions to vaccines. These may occur immediately, as is the case with anaphylaxis, or they could take the form of longer-term conditions such as inappropriate immune responses to the vaccine, resulting in autoimmune conditions such as Guillain-Barre syndrome.
Although one study purported that vaccines caused autism, the study was discredited on the basis of bias and poor design as the doctor responsible used a only small sample group of autistic children as study subjects. The paper and Dr Wakefield’s credentials were subsequently revoked. Many studies have since been conducted, and no links have been found between vaccines and diagnoses of autism.
A typical vaccine reaction may include redness at the site of injection, irritability, loss of appetite, mild fever and fatigue. These are signs that your body is reacting appropriately to the vaccine. There are also other responses that occur in response to particular vaccines. Severe reactions should be reported to your doctor or the medical professional who administered the vaccine. Many countries have specialist databases to track reaction complaints regarding vaccines. If a problem is found, the batch may be investigated, and vaccine guidelines or dosage rates may be reviewed.
If you have any concerns regarding adverse reactions that you or your child may have to a scheduled vaccine, discuss these with your doctor or medical professional. Remain at the medical facility for 10–15 minutes after receiving a vaccine to ensure that there is help at hand in the rare case of an anaphylactic reaction.
If an adverse reaction occurs, your doctor or medical professional will discuss the best course of action going forward, particularly if you or your child were set to receive booster shots for the vaccine that provoked the reaction.
In certain cases where individuals are likely to experience severe reactions or co-morbidities due to other medical conditions, vaccines cannot be administered or repeated. Herd immunity plays a vital in protecting individuals who cannot be vaccinated.
If you missed the first part of this series, where we discuss the components and mechanisms of action of vaccines, head over and take a look at it now. In part 3, we will look specifically at the challenges of designing a COVID-19 vaccine.
If you have any questions about COVID-19, pathogens or vaccines, or would like advice on safely handling hazardous substances, please contact the Chemwatch team today. Our friendly and experienced staff draws on years of experience to offer the latest industry advice on how to stay safe and comply with Health and Safety regulations.