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How long can the immunization of COVID-19 vaccine last?



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Medical staff can be seen at the vaccination site. Gabrielle Lurie/San Francisco Chronicle via Getty Images
  • New research has found that the mRNA COVID-19 vaccine can provide immunity for at least 6 months.
  • But because COVID-19 is so new, experts are not sure whether immunity will weaken afterwards.
  • Experts say that more research is needed to understand whether people need regular booster injections for COVID-19.

The COVID-19 vaccines produced by Pfizer and Moderna are very effective in preventing COVID-19 cases in the real world, and studies have shown that they should maintain their effectiveness over time.

However, it is not clear how long the vaccine will protect against COVID-19, whether booster injections may be needed, or whether the vaccine needs to be adjusted to combat emerging virus variants.

in April 2 report, The Centers for Disease Control and Prevention (CDC) studied nearly 4,000 vaccinated medical staff, first responders, and other basic and frontline workers.

They found that the messenger RNA (mRNA) vaccine developed by pharmaceutical companies Pfizer-BioNTech and Moderna prevented 80% of cases after the first injection and 90% after the second injection.

Frontline workers in the study are tested for COVID-19 for 13 weeks each week.

The researchers said that the lack of COVID-19 positive tests in the research team showed that the vaccine reduced the risk of vaccinators spreading SARS-CoV-2 to others.

“It is especially important for medical staff, first responders, and other basic and frontline workers to reduce the risk of transmission of infections between asymptomatic infected persons or between persons who have been Sexually transmitted viruses maintain close contact with patients and the public.” The report pointed out.

“There is increasing evidence that … the spread of the virus after vaccination may be very low,” said Dr. Susan Bailey, an allergy specialist and immunologist of the American Medical Association, to Healthline.

In addition, Pfizer-BioNTech said that the ongoing phase 3 clinical trials of mRNA vaccines show that in the vaccinated population, strong immunity lasts for at least 6 months.

The researchers found that the vaccine has an effective rate of 100% against severe diseases as defined by the CDC, while an effective rate of 95.3% against severe COVID-19 as defined by the Food and Drug Administration (FDA).

The vaccine was also found to be 100% effective against one of the major COVID-19 variants currently circulating in South Africa (called B.1.351).

The two companies announced that a study involving 12,000 vaccinated people also found that the Pfizer-BioNTech vaccine had no “serious safety risks.”

Bailey said: “The good news is that Pfizer’s 6-month status report shows that immunity is still strong, and we expect it to continue to be strong.”

“these people [in the study] Vaccination takes the longest time, and can tell us that it lasts at least 6 months. Bailey added. “But it’s definitely longer than that-it’s not only going to drop in six months. If the efficiency drops by a third or half, I will be worried. ”

The fact that the effectiveness of the COVID-19 vaccine remained almost unchanged throughout the study period indicates that this protection will last.

Bailey pointed out that certain vaccines (such as measles, mumps and rubella vaccines) usually have lifelong immunity. Other vaccines, such as the flu vaccine, need to be re-injected every year.

She said: “We don’t know which camp the COVID-19 vaccine will fall into.” She added: “If we do need a booster injection of COVID-19, we do know that it will be easy to produce.”

Bailey said the vaccine currently in use appears to be effective against the COVID-19 variant that is circulating in the United States. But as the coronavirus continues to mutate, more resistant variants may emerge.

She said: “My prediction is that in the future we need to intensify injections not because the first dose of vaccine has faded, but because new variants may appear.”

As pointed out in the study, vaccines have not completely eliminated the risk of developing COVID-19.

The recent report of 100 COVID-19 cases among vaccinated people in Washington State has raised public alarm.

But experts say that such “breakthrough” cases are predictable, accounting for only a small percentage of the 1 million Washington residents who have been vaccinated.

“The evidence of the discovery of vaccine breakthrough cases reminds us that even if you have been vaccinated, you still need to wear a mask, keep your distance from society, and wash your hands to prevent the spread of COVID-19 to others who have not been vaccinated,” he said. Washington State Secretary of Health, Dr. Umair A. Shah.


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