Historically, vaccine development has been a prolonged process, often taking years if not decades. However, with COVID-19, using platforms like mRNA technology, vector vaccines, and protein subunit vaccines, several viable candidates were designed within mere months of the virus’s genetic sequence becoming available.
Steps in vaccine development
- Preclinical Testing: Researchers test the vaccine on cells and then on animals to see its efficacy and safety.
- Phase I Trials: The vaccine is given to a small number of people to gauge safety and dosage.
- Phase II Trials: Vaccines are administered to hundreds of people, usually including those of different ages and health statuses, to see their safety and ability to stimulate the immune system.
- Phase III Trials: Thousands of participants are involved, and the vaccine’s ability to prevent the disease is observed.
- Approval: Regulating entities like the FDA, EMA, and WHO review the trial results and decide on emergency use or full approval.
For COVID-19, many of these steps overlapped, allowing for expedited development without compromising on the stringent safety and efficacy criteria. The Food and Drug Administration allowed an Early Use Authorization (EUA) for COVID-19 Vaccines. In a groundbreaking global effort, the scientific community rapidly developed, tested, and distributed vaccines against COVID-19.
The table below summarizes the timeline of rapid development and approval of all COVID-19 vaccines:
|Vaccine||Type||Brand Name||FDA Approval Dates|
|Pfizer-BioNTech||mRNA||Comirnaty||December 11, 2020|
|Moderna||mRNA||Spikevax||December 18, 2020|
|Johnson & Johnson||Viral vector||Janssen||February 27, 2021|
|Novavax||Protein-based||Nuvaxovid||June 23, 2022|
How COVID-19 Vaccines Work
COVID-19 vaccines are a safe and effective way to protect yourself from the coronavirus disease 2019 (COVID-19). COVID-19 vaccines work by priming the body’s immune system to fight the virus.
When you get a COVID-19 vaccine, the vaccine teaches your body’s immune system to recognize and fight the virus. The vaccine does this by exposing your body to a harmless version of the virus or its proteins.
Once your body’s immune system has been exposed to the virus or its proteins, it will start to make antibodies. Antibodies are proteins that bind to the virus and help to destroy it.
If you are later exposed to the virus, your body’s immune system will be ready to fight it off. The antibodies will bind to the virus and prevent it from infecting your cells.
Types of COVID-19 Vaccines
There are currently three types of COVID-19 vaccines available in the United States:
- mRNA vaccines: These vaccines instruct cells to produce a protein resembling the spike protein on the SARS-CoV-2 virus surface, facilitating immune system recognition. The spike protein is what the virus uses to enter cells.
- Viral vector vaccines: These vaccines use a weakened or inactive virus to deliver genetic material into your cells. This genetic material prompts your cells to produce the spike protein .
- Protein subunit vaccines: These vaccines contain a piece of the spike protein that has been made in a lab. The spike protein is then injected into your body.
A fourth type of COVID-19 vaccine made with an inactivated COVID-19 virus was used in other countries. Inactivated virus vaccines use a virus that has been killed to stimulate the body’s immune response.
|Vaccine||Type||Brand Name||Approval Dates|
|Sinovac||Inactivated virus||CoronaVac||December 17, 2021|
|Sinopharm||Inactivated virus||BIBP-CorV||December 20, 2021|
All types of COVID-19 vaccines have been extensively studied and vigorously tested in clinical trials. They are shown to be effective and safe for people of all ages. The duration of protection provided by COVID-19 vaccines is not yet known. However, some studies have shown that the protection can last for several months.
Everyone 5 years of age and older should get a COVID-19 vaccine. This includes people who are healthy as well as people with underlying health conditions. Studies have shown that COVID-19 vaccines are also safe and effective for pregnant and breastfeeding women and their babies. It reduces the risk of serious illness, hospitalization, and death from COVID-19 in all populations.
If you have any questions or concerns about getting a COVID-19 vaccine, talk to your doctor.
These vaccines prevent serious illness, hospitalization, and death from COVID-19. They are also effective at preventing the spread of the contagious virus.
COVID-19 Storage & Refrigeration
COVID-19 vaccines must be stored and handled carefully to maintain their potency. The specific storage requirements vary by vaccine, but they generally require storage in a refrigerator or freezer. Here is a table summarizing this information:
|Vaccine||Brand Name||Storage Temperature|
|Pfizer-BioNTech||Comirnaty||-70°C to -60°C (-94°F to -76°F)|
|Moderna||Spikevax||-20°C to -15°C (-4°F to 5°F)|
|Johnson & Johnson||Janssen||2°C to 8°C (36°F to 46°F)|
|Novavax||Nuvaxovid||2°C to 8°C (36°F to 46°F)|
|Sinovac||CoronaVac||2°C to 8°C (36°F to 46°F)|
|Sinopharm||BIBP-CorV||2°C to 8°C (36°F to 46°F)|
Once the vaccines are removed from the refrigerator or freezer, they must be thawed and used within a certain period of time. The Pfizer-BioNTech vaccine can be thawed at room temperature for up to 6 hours, while the Moderna vaccine can be thawed in a refrigerator for up to 30 hours.
The vaccines have to be handled with care to avoid contamination. They should not be shaken or frozen, and direct sunlight and heat have to be avoided.
Before administering the vaccine, the healthcare provider should check the expiration date and visually inspect the vial for any signs of contamination. The vaccine should be administered immediately after thawing.
It is important to follow the manufacturer’s instructions for the storage, distribution, handling, refrigeration, and thawing of COVID-19 vaccines to ensure their effectiveness.
Effectiveness And Efficacy of COVID-19 Vaccines
Efficacy of COVID-19 vaccines was measured in clinical trials, comparing a vaccine group to a placebo group.
Effectiveness is measured in real-world studies, where participants are not randomly assigned to groups. The effectiveness rate is calculated by comparing the number of people who get sick in the vaccinated group to the number of people who get sick in the unvaccinated group.
The efficacy and effectiveness rates of vaccines can change over time, as the virus mutates and the immune system’s response to the vaccine wanes. Other factors, such as age, underlying health conditions, and the timing of vaccination, can also affect the efficacy and effectiveness of vaccines.
The effectiveness and efficacy of all types of COVID-19 vaccines is summarized below:
|Vaccine||Efficacy (clinical trials)||Effectiveness (real-world studies)|
|Pfizer-BioNTech||95%||91% against symptomatic infection, 95% against hospitalization, 97% against death|
|Moderna||94.10%||93% against symptomatic infection, 96% against hospitalization, 98% against death|
|AstraZeneca||76%||67% against symptomatic infection, 82% against hospitalization, 92% against death|
|Johnson & Johnson||66%||70% against symptomatic infection, 80% against hospitalization, 86% against death|
|Novavax||90%||80% against symptomatic infection, 90% against hospitalization, 95% against death|
|Sinopharm||79%||72% against symptomatic infection, 86% against hospitalization, 91% against death|
|Sinovac||50.40%||50.3% against symptomatic infection, 67% against hospitalization, 80% against death|
COVID-19 vaccines are necessary to protect yourself from COVID-19 and to help prevent the spread of the virus. The benefits of getting COVID-19 vaccines include protection from serious illness, hospitalization, and death from COVID-19.
COVID-19 vaccines are safe and have been rigorously tested in clinical trials. They are effective in preventing the spread of the contagious virus. They may not be 100% protective but they help prevent serious illness, hospitalization, and death from COVID-19.
Side Effects of COVID-19 Vaccines
The most common side effects of COVID-19 vaccines are mild and go away on their own within a few days. These side effects may include pain, redness, and swelling at the injection site, fatigue, headache, muscle pain, chills, fever, and nausea.
Serious side effects from COVID-19 vaccines are very rare
COVID-19 vaccines are accessible at:
- Doctor’s offices
- Community health centers
- Vaccination clinics
The CDC website provides a list of nearby vaccination locations.
These vaccines have showcased what collaboration amongst the scientific community, the Food and Drug Administration (FDA) and the Centers for Disease Control and Prevention (CDC) can achieve. Overall, there was a reduction in COVID cases, protection against new variants, the development of herd immunity as well as the prevention of a long COVID syndrome.
These vaccines helped economic and social rejuvenation by allowing the easing of restrictions. Pockets of challenges in vaccine hesitancy, global distribution, and the emergence of new variants still remain and are being worked upon.
- How long do COVID-19 vaccines last?
It is not yet known how long COVID-19 vaccines last. However, studies have shown that the protection can last for at least 6 months. Some studies have even shown that the protection can last for up to a year.
- Can I still get COVID-19 after being vaccinated?
Yes, it is possible to still get COVID-19 after being vaccinated. However, the vaccine is very effective at preventing serious illness, hospitalization, and death from COVID-19. Even if you do get COVID-19 after being vaccinated, you are likely to have a much milder case of the disease.
- Are COVID-19 vaccines safe for pregnant and breastfeeding women?
Yes, COVID-19 vaccines are safe for pregnant and breastfeeding women. Studies have shown that the vaccines are effective at protecting pregnant and breastfeeding women from COVID-19, and they do not harm the baby.
- Can I mix and match COVID-19 vaccines?
Yes, it is safe to mix and match COVID-19 vaccines. Studies have shown that mixing and matching COVID-19 vaccines is just as safe and effective as getting two doses of the same vaccine.
- What are the side effects of COVID-19 vaccines?
The most common side effects of COVID-19 vaccines are mild and go away on their own within a few days. These side effects can include:
- Pain, redness, and swelling at the injection site
- Muscle pain
Rare side effects have also been reported, such as myocarditis (inflammation of the heart muscle) and pericarditis (inflammation of the lining around the heart). However, these side effects are extremely rare, and the benefits of the vaccine far outweigh the risks.