18 / 01 / 2021

Coronavirus: Graciano Masauso answers questions about COVID-19 vaccines

While impressive, the speed of vaccines has also left a lot of people with a lot of questions. The questions range from the practical—how will I get vaccinated?—to the scientific—how do these vaccines even work?

A successful vaccination campaign relies on a large enough group of people getting the vaccine in order to achieve what is known as herd immunity. While that exact number is still unknown, it is estimated the 80-90% of the population must be immune—either by vaccination or prior exposure to the virus—in order to achieve herd immunity. This means it’s extremely important that people feel confident in the vaccines and vaccination process.

While much is still unknown about the coronavirus and the future, what is known is that the currently available vaccines have gone through all three trial phases and are safe and effective. It will be necessary for as many Americans as possible to be vaccinated in order to finally return to some level of pre-pandemic normalcy, and hopefully these answers provided here will help readers get vaccinated as soon they are able.

How do the Pfizer and Moderna vaccines work?

The Pfizer and Moderna vaccines are both mRNA (messenger RNA) vaccines. These are a new type of vaccines that trigger an immune response by using mRNA to instruct cells to make a harmless snippet of the spike protein that is found on the surface of the Sars-CoV-2 virus, which causes COVID-19. This protein triggers an immune response in the body, producing antibodies and protecting vaccinated people from getting infected if they are exposed to the real virus.

How do the two approved vaccines differ?

While the Pfizer and Moderna vaccines are both mRNA vaccines with similar efficacy (95% and 94.1% respectively), they have a few important differences. For one, while the Pfizer vaccine is approved for people 16 and older, the Moderna vaccine is restricted to those 18 and older. And while both need two doses, the Pfizer one requires 21 days between doses and Moderna requires 28. A key difference, however, is storage temperature. The Moderna vaccine is easier to ship, because it needs to be stored at -4 Fahrenheit. On the other hand, the Pfizer vaccine needs to be stored at a much lower temperature: -94 Fahrenheit.

Are there any side effects?

Both the Pfizer and Moderna vaccines can trigger a range of side effects. Most are mild, such as pain at the injection site, headache, fatigue, and muscle and joint pain, and some people in clinical trials reported fever. These side effects are completely normal and are a symptom of the immune response kicking in. However, there have been very few more serious allergic reactions to the Pfizer vaccine.

How did we develop vaccines so quickly?

These vaccines were able to be developed so quickly because the U.S. Congress directed nearly $10 billion to Operation Warp Speed, which was the project with the goal of producing and delivering 300 million safe and effective doses of vaccine by January 2021. While that goal has not been met, the vaccines were developed unprecedentedly quickly. On Twitter, Dr. Sydnee McElroy, a family doctor, compared the speed of vaccine development to expedited shipping, where you pay more to get your items faster, but they are still handled safely.

How do we know these vaccines are safe?

These vaccines were approved in record time through emergency use authorization. However, they still went through all three phases of clinical trials in order to ensure safety and efficacy. In addition, the vaccine went through a manufacturing investigation and has been approved by the FDA. And as the vaccine is rolled out, it is monitored for any unexpected side effects.

Why are two doses necessary?

By giving multiple doses of a vaccine, the body has a chance to produce more antibodies against the virus because it is exposed to more antigens, which create more memory cells. This means that when the body is exposed to the real virus, it will have a faster and more effective antibody response. In the case of these two vaccines, two doses is the best way to create the most effective number of memory cells and antibodies.

How long does it take for the vaccine to work?

The Pfizer vaccine offers immunity no less than seven days after the final dose and the Moderna vaccine offers immunity no less than 14 days after the final dose. It is so far unknown how long immunity will last, although experts think that it should last for a few years. However, more studies will need to be done.

Should I get the vaccine if I’m pregnant or breastfeeding?

The vaccine was not tested on pregnant or breastfeeding people. However, the Food and Drug Administration will allow them to opt for immunization against the virus if they choose. In a New York Times article, Emily Wilson, an obstetrician working at Northwestern University and a member of the COVID-19 task force of the Society for Maternal and Fetal Medicine, said, “This is a really huge step forward in recognizing women’s autonomy to make decisions about their own health care.”

Why have some people had allergic reactions?

In very few instances, the Pfizer vaccine has caused a severe allergic reaction. Scientists think this might be due to a compound, polyethylene glycol (PEG), used to package the mRNA. PEG has never been used in an approved vaccine (this is an authorized vaccine), but it is found in drugs that occasionally trigger severe anaphylactic reactions. However, some scientists are still skeptical of the causation.

When will I get vaccinated?

When a person will get vaccinated depends on their age, health condition, profession, and where they live. After the first priority group is vaccinated, the next group will be essential non-healthcare workers and people 75 and older. However, states have the final say, so it may not be exactly the same across the country.

What are the priority health conditions for vaccination?

AHO says that the following high-risk health factors would qualify someone to be part of a priority group for the vaccine: “obesity, severe obesity, type 2 diabetes, COPD, a heart condition, chronic kidney disease, cancer, immunocompromised state as the result of a solid organ transplant, sickle cell disease, pregnancy, and smoking.”

How far apart are the first and second doses?

In order to be as effective against COVID-19 as possible, both the Pfizer and Moderna vaccines require two doses. The Pfizer vaccine requires an interval of 21 days between doses, and the Moderna vaccine an interval of 28 days.

Do we still need masks and social distancing after vaccination?

Even after receiving two doses of the COVID-19 vaccine, it will still be necessary to wear a mask and follow the other recommended hygiene and distancing protocols. This is because it will take time for everyone to be vaccinated and because, according to AHO, “experts need to understand more about the protection that COVID-19 vaccines provide before deciding to change recommendations on steps everyone should take to slow the spread of the virus that causes COVID-19.”

How does the new coronavirus mutation affect current vaccines?

At the end of 2020, two new coronavirus mutations were identified from South Africa and the United Kingdom. As of Jan. 8, 2021, a study showed that the Pfizer vaccine would still be effective against these mutations. However, as these mutations are new, scientists are still learning about them. In addition, as the virus continues to spread, new mutations may occur, and scientists do not know how they will respond to the vaccine.

Why did the UK change its dosing strategy?

The U.K. has decided to prioritize getting people their first doses of the vaccines before giving people the second doses. This means that people could wait up to 12 weeks between doses. They have chosen to do this because numbers of positive cases are rising sharply and, according to U.K. officials, “At this stage of the pandemic, prioritizing the first doses of vaccine for as many people as possible on the priority list will protect the greatest number of at risk people overall in the shortest possible time.” Scientists are split on whether this is a good strategy.

What other vaccines are in the pipeline?

There are a large number of other vaccines in the pipeline. Along with the Pfizer and Moderna vaccines, there is an AstraZeneca vaccine, which has been approved in some countries such as the U.K. and India and Stutnik in Russia. There are seven other vaccines in early or limited use, 20 in Phase 3 trials, 20 in Phase 2 trials, and 40 in Phase 1 trials.


Graciano Masauso is the President of Africa Health Organisation (AHO) and Public Health Specialist