Why didn't Pfizer and Moderna have new vaccine against Delta variants?

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Why didn’t Pfizer and Moderna have new vaccine against Delta variants?

78-year-old Biden received a booster shot. Why didn’t the pharmaceutical companies have a new vaccine against Delta variant?

On the afternoon of September 27 (Monday), 78-year-old US President Biden received a booster shot of the COVID-19 vaccine at the White House. Just a few days ago, the United States just approved a booster shot for people over 65 years of age and other high-risk groups.

Why didn't Pfizer and Moderna have new vaccine against Delta variants?

Biden also joked that his age is “far more than” 65 years old, which is why he is eligible for the booster shot. Before he took office as president in January this year, Biden had already received two shots of Pfizer vaccine, and the two vaccinations had no side effects. First lady Jill Biden also received a booster shot late Monday.

At the same time as the launch of the booster shot, the United States will significantly increase the number of COVID-19 vaccines shipped to foreign countries from 2022.

Biden announced last week that the United States will purchase an additional 500 million doses of Pfizer’s COVID-19 vaccine and donate it to low- and middle-income countries.

WHO Director-General Tedros Adhanom Ghebreyesus once again called on the 27th that, at least until the end of this year, countries should suspend vaccination and bolster injections so that they can be allocated to vulnerable countries.

Since May this year, the highly contagious delta variant of the COVID-19 virus has caused a new wave of epidemics in many countries, infecting a large number of people who have been vaccinated around the world, pushing up the demand for vaccination booster shots.

It was also said that what should be vaccinated is a new version of the vaccine specially developed for the delta variant. In fact, vaccine manufacturers such as Pfizer and Moderna are developing vaccines for delta variants, but the US media VOX analysis believes that the demand for vaccines specially tailored for Delta is not as high as imagined.

Pfizer and BioNTech are testing a new version of the vaccine against the delta variant, and clinical trial results are expected to be announced in the fourth quarter of this year. A vaccine against the beta variant is also under study.

Moderna also announced that it is testing new vaccine formulations for beta and delta variants. Three of the company’s four candidate vaccines have entered phase II trials.

At the same time, the two vaccine manufacturers also pointed out that the original version of the vaccine is effective after the booster shot. Pfizer said that the third dose of vaccine for 18 to 55-year-olds can increase antibodies against delta variants by a factor of 5 and 11-fold for those aged 65 to 85. Moderna also said that after the third booster shot, antibodies against the delta variant increased 42 times.

A new study published by Ian Foster of Argonne National Laboratory and colleagues on the medical preprint website MedRxiv shows that the negative impact of delta variants on vaccine effectiveness in the United States is negligible. From mid-May to mid-August this year, when the delta variant gradually became the main transmission strain, the effectiveness of all vaccines was still as high as 84.1%.

Dan Barouch, an immunologist at Beth Israel Deaconess Medical Center in the United States, further explained that the effect of the vaccine against the delta variant may not be much better than the original vaccine. Because the spike protein of Delta is very similar to the original new coronavirus in appearance and shape.

In addition, although the mRNA vaccine technology used by the above two companies can ensure that the development of improved vaccines is faster than traditional vaccines and the clinical trial process is shorter, it takes at least several months from experimentation, production to regulatory approval.

Boston University epidemiologist Benjamin Linas (Benjamin Linas) said that another reason for not producing delta vaccine is that it may send the wrong signal to the public that “the original vaccine is no longer working.” And there are still a large number of original vaccines that have been produced that have not been used. If people only accept the “improved” new version of the vaccine, then the original vaccine stock will be wasted.

Angela Rasmussen, a virologist at the University of Saskatchewan, pointed out to VOX: “We don’t need a specific vaccine for Delta… What we need now is the third vaccination. Opportunities, not waiting. This is especially true for high-risk groups.”

Why didn’t Pfizer or Moderna develop new vaccine against Delta variants?

(source:internet, reference only)

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