Illustration: Needle in COVID molecule

The development of a new COVID-19 strain is not unique — new strains, or variants, occur in all viruses. And the scientists studying the disease and developing COVID vaccines have always anticipated that new strains would evolve.

Viruses mutate when they replicate and create a slightly different version of the virus.

Sometimes, these variant strains just disappear; these are the viruses that don't make the news and scientists are not worried about.

But occasionally, variant viruses thrive, meaning that they survive better than, and can out-compete, the original virus. They can become more infectious than the original strain. And the effectiveness of the current COVID vaccines may or may not be reduced in these new strains.

That being said, vaccines are still our most powerful tool to fight all the strains of COVID-19.

What Are the New COVID Variants?

Many variants of COVID-19 have been discovered. But we are currently tracking three:

  • UK Strain – The United Kingdom variant spreads more easily and quickly than others. Currently, there is no evidence that it causes more severe illness or increased risk of death.
  • Brazil Strain – The Brazil variant contains more mutations than the UK strain that may affect its ability to be blocked by therapeutic antibodies or a vaccine.
  • South African Strain – The South African variant shares some mutations with the Brazil variant and is a similar threat.

Currently, both the UK and South African strains have been identified in Maryland.

Do the Vaccines Work Against the New Strains?

The simple answer is yes. How (and how well) they work against these new strains requires a more complex explanation. The key points are:

The vaccines are still highly effective.

The effectiveness of the currently authorized vaccines is quite high, even if it is somewhat lower against new strains. The nearly 95 percent effectiveness of the Pfizer and Moderna vaccines is much higher than is typical for vaccines. As a reminder, the annual flu vaccine has an effectiveness around 40-60 percent from year to year.

Although the antibodies created by the vaccines did not block the virus as well in the South African and Brazil strains, keep in mind that the antibodies that fight the virus aren't the only part of a vaccine that makes it effective.

These vaccines provoke such a powerful immune response, using T cells, memory B cells and other types of antibodies, so that they remain highly protective even if there's a drop in antibody strength.

The vaccines prevent hospitalization and death.

Even if the vaccines are less effective against a particular strain, they still protect quite well against hospitalization or death from the virus in these new strains.

This is a critical point. Not only will this help relieve the strain on the healthcare system, it means fewer people may die from the disease as more people are vaccinated.

The vaccines help stop new variants.

As we vaccinate as many people as possible, as quickly as possible, we can stop the spread of the coronavirus. A slow in transmission of the virus means fewer opportunities for it to mutate, which can help prevent the emergence of any other variants.

The vaccines can be updated to be more effective.

Research continues on all the vaccines. New formulations or booster shots may be developed that enhance their effectiveness. Learn more about how the vaccines were developed.

mRNA vaccines, which is the technology used by Pfizer and Moderna, can be reformulated much faster than vaccines using more traditional methods. Both Pfizer and Moderna are already looking at what a booster might look like down the road.

Reducing the Spread of COVID

The best way to protect yourself and others from the virus – whatever the strain – is to get the vaccine when it is available to you.

Also, to reduce the spread of this disease, we need to continue to follow all of the public health measures that we know of, such as wearing a mask, social distancing and avoiding large gatherings, even after you are vaccinated.

Updated 2/9/2021

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