Pfizer's vaccine booster shot significantly increase resistance to Omicron?

Researchers at Sheba Hospital (Israel) on December 11 published a preliminary study showing that a booster shot of Pfizer's vaccine can significantly increase resistance to Omicron. However when comparing with Delta, the effectiveness of Pfizer's vaccine "defense" against Omicron is 4 times lower.

According to the VNA, the research project led by Dr. GiliRegevYochay—Director of the Center for Infectious Diseases Epidemiology—took blood samples from 40 medical staff at Sheba Hospital. Half of whom were injected with the booster dose (3rd dose) to prevent COVID-19 a month ago, and the other half just got the 2nd dose 5–6 months ago.

The results showed that the antibodies of people who received only 2 injections could not fight the Omicron variant, although they were still able to fight the Delta variant and the original strain of the SARS-CoV-2 virus.

For people who have been injected fully 3 doses, there is an ability to create antibodies for Omicron, but it is 4 times lower than for Delta.

The result of this study is similar to that of Pfizer's previous research, which confirmed that its vaccine is also capable of preventing the Omicron variant.

However, the result of the above study is just preliminary. Besides, the team of experts say it is still unclear how the immunity systems of people who received two injections react to the new variant.

At a time when there is no effective vaccine against Omicron, this study will be a premise for governments of countries to consider having booster vaccination for their citizens at an appropriate time to ensure maximum health of people.

Israel started to deploy additional injections as a 3rd dose for citizens last August. There are still millions of people who are eligible for additional shots but have yet to get one.

On December 11th, the Israeli Ministry of Health announced that a total of 55 Israelis were infected with the Omicron variant. 36 of whom returned from abroad, including South Africa, the UK, France, USA, UAE, Belarus, Hungary, Italy, and Namibia; 11 cases of secondary infection from returnees from South Africa and the UK; and 8 cases got infected by community transmission.

Facing the threat of a new variant of Omicron that could cause a 5th wave of epidemics, Israeli authorities are considering the possibility of tightening control measures and considering an additional vaccine injection after 3 months instead of 6 as current policy.

Pfizer's vaccine booster shot can significantly increase resistance to Omicron.

According to the VNA, the first study by the UK Health Security Agency (UKHSA) on the effectiveness of the vaccine against the new variant showed that out of 581 people with the Omicron variant who received two doses of AstraZeneca or Pfizer/BioNTech, the protection of symptomatic cases was much lower than that of the Delta variant, but the level increased to 70–75% two weeks after they received their third dose.

Research shows that Omicron variant transmission among close contacts is twice as high as the Delta variant. Besides, initial analysis shows that people who have recovered from COVID-19 are more likely to be re-infected with Omicrons than the Delta variant.

UKHSA also forecasts that Omicron will overtake Delta to become the dominant variant by mid-December. They warn that at the current rate of Omicron cases, which is doubling every 2-3 days, the number of cases of this variant in the UK will surpass 1 million by the end of this December.

Dr Mary Ramsay, head of immunization at UKHSA, said this initial data should be considered carefully. However, the data has already shown that people who have had two doses of the COVID-19 vaccine have a greater risk of having the Omicron variant than the Delta variant.

The Minister of Health of the UK, SajidJavid, emphasizes the importance of the booster dose against this new variant through this new data.

Scientists and health competent authorities in the UK say the rise in infection rates could quickly put pressure on the National Health Service (NHS). On December 10th, the UK recorded 58,194 new cases of COVID-19, mostly with the Delta variant. This is the highest number of new cases per day in the UK since January 9th.

Professor of genetic epidemiology at King's College London, Tim Spector, thinks the government will be forced to take additional measures to bring down the Omicron variant and reduce cases if hospitalizations increase.

Meanwhile, Matthew Taylor, CEO of the NHS Confederation, warns that the Omicron variant could make the "unprecedented challenge" become "impossible to deal with" for the NHS.

He welcomed the government's action earlier this week to activate Plan B to prevent COVID-19, which included regulations on wearing masks, working from home, and "vaccine passports." However, he also emphasized that the government should be ready to take further restrictive measures if necessary.

Professor Spector added that although the UK had "already paid the price" for the wave of outbreaks in the summer and autumn, the additional immunity would help the country overcome the Omicron wave.

Marc Baguelin, a lecturer in infectious disease modeling at London's Imperial College and a member of the government's Influenza Epidemic Modeling Scientific Research Group, said that even in the most optimistic scenario, the number of cases and hospitalizations would still increase, but not surpass the peak of the epidemic wave in January. According to him, the booster injection will be crucial to deal with the new variant.

As of December 10th, nearly 22.2 million Britons (38.6% of the population) had received a booster shot of the COVID-19 vaccine. Nearly 46.7 million people (more than 81%) have had 2 injections, and more than 51.2 million people (89%) have had 1 injection.

Source: Cổng thông tin điện tử Chính phủ

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