Covid-19 Vaccines: What You Need to Know

Written by Christie Hsiao

NowRx Pharmacy

Covid-19 Vaccines_ What you need to know blog image

In late December, US regulators granted emergency-use authorization for the country’s first Covid-19 vaccines.

Since then, a number of common questions have popped up.

How effective is each vaccine? Are they safe? How and when will the vaccines be distributed?

Here are your answers to the most common Covid-19 vaccine questions.

What Are the Types of Covid-19 Vaccines?

Right now, there are two types of Covid-19 vaccines available in the US – Pfizer and Moderna.

The Pfizer and Moderna vaccines were recommended by the CDC and granted emergency-use authorization by the FDA in late December. Distribution followed within weeks to limited populations. 

Each state is responsible for deciding how and when to distribute the vaccine to residents. However, the CDC has proposed a phased rollout in order to prioritize at-risk groups.

The CDC recommended that the first wave of vaccinations (Phase 1a) go to healthcare personnel and long-term care facility residents. After that, in phase 1b, frontline health workers and people over the age of 75. Finally, phase 1c of the vaccination rollout would include people ages 65-74 and individuals with underlying medical conditions.

So far, distribution has been successful with limited reports of adverse reactions.

Additionally, Johnson & Johnson has developed a single shot Covid-19 vaccine. Regulators are expected to review and approve or deny emergency authorization in early February. 

If Johnson & Johnson receives approval, many expect the vaccine would begin distribution in early March.

How Do Covid-19 Vaccines Work?

The Pfizer and Moderna vaccines are both mRNA vaccines, which is a new type of vaccine created to protect against infectious diseases.

Typically, a vaccine places a weakened or inactive germ into our bodies. The germ then triggers an immune response, which causes us to produce antibodies. These antibodies then protect us against future infections. Simple enough right?

However, mRNA vaccines are a little bit different.

Instead, an mRNA vaccines teaches our cells how to make a protein, or a piece of a protein.

In the case of Covid-19, this is a harmless piece of what is called the “spike protein”, which is found on the surface of the virus.

This harmless piece of the “spike protein” triggers an immune response, which causes our bodies to build T-lymphocytes and B-lymphocytes that will remember how to fight the virus that causes Covid-19 in case we are infected in the future. This is a simplified explanation but you get the picture.

If you want to learn more about how Covid-19 vaccines work, the CDC has provided a great resource here.

What Are the Age Groups for Covid-19 Vaccines?

Individuals 16 and over can take the Pfizer vaccine. However, only individuals 18 and over can take the Moderna vaccine.

Additionally, the CDC has recommended that initial vaccinations should be offered to those 75 years and older. Although, this is just a recommendation. Each state will handle distribution based on availability and priority of at-risk groups.

To learn more about age groups and vaccine distribution timelines, check your state’s official website.

How Many Doses for Both Covid-19 Vaccines?

Both the Pfizer and the Moderna vaccines require two shots to maximize efficacy.

For the Moderna vaccine, it is recommended that the doses be separated by at least 28 days. For the Pfizer vaccine, it is recommended that the doses be separated by at least 21 days. It is unclear how effective the vaccine will be if you do not follow exact dosing timelines.

The Johnson & Johnson vaccine will be a single-dose, but is not expected to be available before early March. 

Which Covid-19 Vaccine is Most Effective?

Although each vaccine differs in its ability to reduce the risk of death or severe Covid-19, these differences seem to be minor.

The Pfizer vaccine has shown an efficacy of 95% in preventing symptomatic Covid infection after two doses, while the Moderna vaccine is slightly lower at 94.1%. Additionally, both vaccines seem to be more or less the same across age, racial, and ethnic groups.

The highly anticipated Johnson & Johnson vaccine is slightly less effective according to studies. The company reported that the single-dose vaccine is 85% effective at preventing severe disease or death from Covid-19. However, the shot was only 57%-72% effective in preventing moderate disease.

These efficacy rates are for symptomatic disease only. At the moment, it is not known how well the vaccine protects against asymptomatic disease, which is estimated to account for some 40% of cases.

In addition, it is unclear how effective the two-dose vaccine will be if you do not follow exact dosing timelines.

Are There Any Side Effects for Both Vaccines?

Unfortunately, both the Pfizer and Moderna vaccines have had reported side effects.

But thankfully they seem to be relatively minor and affect only a small percentage of those vaccinated.

On the vaccinated arm, the most common side effects have been pain and swelling. Throughout the rest of the body, the most common side effects have been fever, chills, tiredness, and headaches. Overall, these seem to affect young adults more than old adults.

In most cases, these symptoms are completely normal. It is a sign that your body is building protection and the vaccine is working. You should expect the symptoms to go away within a couple days.

However, if the side effects are worrying you, contact your doctor or healthcare provider. Additionally, if the redness or tenderness from the shot increases after 24 hours, you should contact your doctor or healthcare provider.

In rare cases, some individuals have reported severe life-threatening allergic reactions. Through the first 2M vaccinations, there were roughly 21 cases of reported allergic reactions. Over 71% of these reactions occurred within 15 minutes of vaccination.

If you think you are having an allergic reaction after receiving a vaccine you should seek immediate medical attention.

Where Can I Learn More About the Covid-19 Vaccines?

There are a lot of great resources online to learn more about the Covid-19 vaccine.

The CDC provides links and answers to a variety of questions and topics surrounding each vaccine. You can find these at

We have included some additional great resources below.

Alternatively, if you have any questions, please reach out to your local NowRx Pharmacy. Our pharmacists are highly accessible and always happy to help in any way we can.

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