COVID-19 : Variants of the coronavirus and their possible resistance to vaccines

The factor that explains the appearance of variants in dissimilar points of the planet 27:27

(CNN Spanish) – The appearance of variants of the new coronavirus has pharmaceutical companies evaluating whether or not they should change their already approved vaccines. Scientists are studying whether the South African and Brazilian variants are resistant to vaccines already developed against the disease.

In this episode Dr. Elmer Huerta reviews recently published research studying the Pfizer / BioNTech vaccine.

You can listen to this episode on Apple Podcasts, Spotify, or your favorite podcast platform, or read the transcript below.

Hello, I am Dr. Elmer Huerta and this is your daily dose of information on the new coronavirus. Information that we hope will be useful to take care of your health and that of your family.

One of the aspects of greatest concern to vaccine experts is the real possibility that new variants of the new coronavirus may be resistant to the first-generation vaccines that are being developed and applied.

Coronavirus Variants and Vaccines: What Scientists Study

Proof of this concern are the studies that pharmaceutical companies are doing, to determine if their vaccines are active against the variants of the new coronavirus, especially B.1.351, discovered in South Africa and P.1, discovered in Brazil.

In this sense, the New England Journal of Medicine, of February 17, publishes a study in which researchers associated with the manufacturers of the vaccine Pfizer and BioNTech, show that their vaccine – despite being active – is approximately two-thirds weaker to neutralize the South African variant of the virus.

One of the study authors told CNN that, while it is not yet known exactly what level of neutralization is required to protect against SARS-CoV-2 infection, it is likely that Pfizer’s vaccine offers relatively good protection against this new variant.

But what does the appearance of these new variants mean in the immunization strategy against the new coronavirus? Will it be necessary to change all the first generation vaccines that are being developed?

We think there are two questions that we must answer.

Variants and strategy to combat coronavirus

The first is whether current and future variants can not be neutralized by antibodies produced in response to natural disease, and therefore, it is possible to be reinfected with these new variants.

The second is whether these variants can escape the neutralizing antibodies produced by vaccination, in which we have placed so much hope to control the pandemic.

Regarding the first, despite the fact that reinfections are a scientifically proven fact, the cases confirmed with comparison of the genomic sequence of the first and second viruses are less than 50.

Despite hundreds of suspected cases, there is no evidence that reinfections are occurring in the thousands or millions. Its true frequency, especially of asymptomatic infections, is not exactly known.

Should the vaccines be changed to attack the variants?

Regarding vaccine response, data from phase 3 studies indicate that the Johnson & Johnson vaccine decreased severe and severe cases of COVID-19 by:

57% in South Africa and 72% in the United States.

While the Novavax vaccine provided a level of protection against mild and moderate to severe COVID-19 infection from:

60% in South Africa and 89.3% in the United Kingdom.

Recall that variant B.1.351 currently represents 80 to 90% of circulating viruses in South Africa.

In addition to phase 3 studies, Israel provides us with data on the effectiveness of the vaccine in the real world, and it is very encouraging to learn that – despite laboratory data that would indicate otherwise – it appears that the SARS-CoV-2 vaccines are working.

For example, after receiving two doses of the Pfizer vaccine, from mid-January to early February, infections in people over 60 years of age decreased by 41%, and hospitalizations decreased by 31%.

In people younger than 59, who were vaccinated later, infections were reduced by only 12% and hospitalizations by 5%.

Will First Generation Vaccines Be Obsolete?

In another study, not yet peer-reviewed, the Pfizer-BioNTech vaccine was found to be 66% to 85% effective in preventing symptomatic infections and 87% to 96% effective in preventing serious disease.

Due Since the vaccines being developed are directed against the spike of the virus, and that variants with the E484K mutation, which evades the action of neutralizing antibodies against the virus, are being produced very rapidly, it is feared that first-generation vaccines may become obsolete in the near future.

As we saw in the February 9 episode, the South African Government had to temporarily suspend the vaccination program with the AstraZeneca / Oxford vaccine, because it was not effective against variety B.1.351, and the manufacturers have said they are prepared. to develop next-generation vaccines.

In summary, it is very likely, experts say, that – as with flu vaccines – we have to be vaccinated annually with multi-purpose vaccines that contain two or three varieties of coronavirus.

Do you have questions about covid-19?

Send me your questions on Twitter, we will try to answer them in our next episodes. You can find me at @DrHuerta.

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