COVID-19 vaccines: two experts answer the most frequently asked questions

Never before has the process of detecting, producing, distributing and applying a vaccine to all of humanity been like it is today. Previous experiences are partially applicable and today the way the coronavirus has spread and the consequences of the pandemic are approaching an invisible international collapse. The speed with which science reacted to find out about the virus and how to fight it in a race against time which, in addition, has undergone the scrutiny of the planet.

With vaccines already approved and starting to circulate, but not with the expected efficiency, speed and justice, questions follow one another in terms of efficacy, implications, applications, reactions.

The lack of messaging combined with the range of different COVID-19 vaccines, the emergence of new variants of the coronavirus, and inconsistent implementation plans from states and municipalities have created confusion. La publicación Scientific American le pidió a Namandjé Bumpus, farmacólogo de Johns Hopkins Medicine in Baltimore, y Ashley Lauren St. John, inmunóloga de la Escuela de Medicina Duke-NUS in Singapur, que respondieran algunas de las preguntas más significant sobre las vacunas COVID available currently. In a collection of their answers in unison, this basic questionnaire is formed to dispel the most important doubts still in the collective mind.

Should I get a licensed COVID vaccine now if eligible?

Yes! It really takes more people to get vaccinated to boost the herd’s immunity and slow the spread of the disease. Vaccines are an important part of the pandemic toolkit.

Should You Get Vaccinated If You Have Ever Had COVID-19?

The United States Centers for Disease Control and Prevention has not suggested a minimum interval between recovery from COVID and vaccination. The symptoms should go away and you should be out of quarantine before getting one. It may be true that you can wait longer because you have a built-in immune response.

How should you interpret the effectiveness of the vaccine? What does “95% effective” or “66% effective” mean?

Vaccine efficacy refers to its performance in a carefully controlled trial, while efficacy describes its performance in the real world. A common misconception is that 95% effectiveness means that you have a 5% chance of getting sick even if you get the vaccine. This is not at all true. Efficacy is calculated based on trials that have an unvaccinated placebo control group and at the end of the trial they look at the number in the control group that ended up with symptomatic COVID to get the rate initial infection. The Pfizer-BioNTech vaccine, for example, was 95% effective in its clinical trial. This number comes from the fact that 162 people in the placebo group contracted symptomatic COVID, and eight people in the vaccinated group did so; this is 170 cases in total. Eight is about 5% of 170. This is basically how efficiency is calculated. Most clinical trials of the COVID vaccine have reported its effectiveness in preventing any symptomatic illness, not necessarily serious illness; however, early data from the latter are promising.

If the vaccine is received and the subject is still infected, does the vaccine still make a difference? Does it prevent serious illness or death?

Yes, what has been observed with most current vaccines is less severe symptoms and almost no hospitalization or death in those vaccinated who are infected. Several trials have observed a reduction in severe illness in vaccinated subjects. With a few exceptions, like possibly the AstraZeneca vaccine in South Africa, the vaccines appear to reduce the risk of getting symptomatic COVID, but if you do, it’s likely a less severe case.

Do vaccines protect against newer variants of the virus, including those first identified in the UK, South Africa and Brazil?

Data to date suggests that most vaccines offer at least some protection against the newer variants. However, it appears from some of the data from clinical trials and antibody neutralization studies that vaccines designed against the parent virus strains may not be as effective against some newer variants, particularly against mutations found in the virus. variant. B.1.351 widespread in South Africa. Most of the newer variants have changes in the spike protein, which the virus uses to infect cells, making it slightly different from what a vaccinated person’s body has seen before in the vaccine. However, in general, licensed vaccines meet efficacy goals and appear to offer some protection against newer variants. The best way to prevent new variants from appearing is to immunize many people. Moderna is developing a booster vaccine to provide additional protection if needed, and Pfizer-BioNTech is also exploring this possibility.

What is the difference between mRNA vaccines and viral vectors?

An mRNA vaccine, like those made by Pfizer-BioNTech or Moderna, provides genetic instructions to produce viral proteins as single-stranded RNA, in a lipid layer, in your cells, without injecting viruses. This has some interesting benefits because it only contains the components of the virus that you want the immune system to recognize and causes your own cells to mimic the way viral proteins are produced when a cell is naturally infected with the virus. It is very effective at inducing the same type of immune response that would occur in a natural infection. One drawback is that mRNA must be stored very cold to be stable.

Viral vector vaccines, like those made by AstraZeneca or Johnson & Johnson, use double-stranded DNA instead of RNA, but they still pass genetic instructions to your cells. They use a safe and modified virus (not SARS-CoV-2) to give instructions for making viral proteins.

Is there a “better” vaccine?

Different vaccine models are chosen because they have unique advantages, so there is no “best” one, but there could be one that is aimed at a certain group of people. TThe mRNA and viral vector vaccines instruct their cells to produce fragments of the coronavirus spike protein so that the next time the body encounters these proteins, it can generate an immune response. The efficacy figures are derived from different clinical studies conducted in different settings, so rather than comparing these figures, it should be remembered that licensed vaccines generally work. They are effective.

Will the vaccine prevent spreading the virus to other people?

We hope so, but we don’t quite know yet. Vaccines have two key purposes: to protect the individual and to stop the spread of disease. We have reason to be hopeful based on what we know about viruses and some emerging data, but we don’t yet know whether vaccines will reduce the transmission of the disease. This is why it is important to pursue social distancing, wear masks and follow other guidelines to prevent the spread of the disease, even if a subject has been vaccinated.

Will the effectiveness of the vaccine decrease over time?

It could happen. They often need booster doses to provide the best levels of protection. Some can protect someone for life, while others require a booster every few years. It will be important to monitor long-term immune responses in those vaccinated to see if and when boosters are needed. Most of the COVID vaccines currently available require two doses to be fully effective. The CDC recently expanded the recommended allowable interval between doses due to limited availability, although some experts have criticized the decision.

Should you be concerned about allergic reactions to the vaccine?

Allergic reactions can occur in response to any vaccine or drug injected, but they are extremely rare. Vaccines should always be given in an environment where healthcare providers can treat any allergic reaction that develops unexpectedly. People don’t have to worry about getting vaccinated if they have food allergies or latex allergies. Most people don’t have to worry about an allergic reaction. For those with a history of severe allergic reactions or allergies to vaccine ingredients, it would be best to discuss this with a doctor before receiving the COVID vaccine.

What side effects might you experience? Are they normal?

Common side effects are what we would expect from other vaccines: fatigue, headache, fever, especially after the second dose, and severe pain at the injection site, which may be warm to the touch and swollen; All of these symptoms are signs of an immune reaction. These reactions are very common and often indicate that the immune system is working hard to recognize the vaccine and remember the new virus for the next time.

How can people make sure they are getting a legitimate, licensed vaccine?

It is always important to get vaccinated under the supervision of a licensed healthcare professional. Consult your doctor with any concerns as there are clear vaccine distribution plans in most places.

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