In the context of the widespread Omicron strain, experts believe that the best protection is to get a full dose of vaccine and repeat vaccination with a booster dose a few months later.

Research by Israel and the US shows that immunity from vaccines will wane after 6 to 8 months.

Booster vaccine doses help restore post-vaccination antibodies to peak levels, effectively preventing Omicron.

`Antibodies reach their highest level 10 to 14 days after injection, then everything will level off. Antibodies then decline, but a booster dose will help them stabilize again,` Dr. Simone Wildes, expert

`Vaccines protect users from infection or at least keep them from becoming seriously ill after infection. Regardless of the strain, Delta or Omicron, the booster dose is beneficial,` said Leo Poon, a virus expert at the University of Hong Kong,

The Covid-19 vaccine trains the immune system to make antibodies using a combination version of the nCoV spike protein – the component that helps the virus bind to cells.

For mRNA vaccines like Pfizer or Moderna, the first dose of vaccine mobilizes cells to make antibodies.

Medical staff prepare a dose of Covid-19 vaccine in Southfield, Michigan, USA, September 29.

But antibody levels for all vaccines gradually decrease, according to Maria Elena Bottazzi, a vaccination specialist at the Texas Children’s Vaccine Development Center, Baylor College of Medicine.

Countries around the world mainly vaccinate booster doses for people aged 18 years and older.

The Pfizer vaccine booster dose increases the amount of antibodies 25 times, enough to neutralize Omicron.

`While two doses of the vaccine remain effective against severe symptoms due to Omicron, preliminary data shows that our third dose improves antibody levels,` said Pfizer CEO Albert Bourla.

The Moderna vaccine booster dose also improves the ability to neutralize the Omicron strain compared to the previous two shots.

`Immunity from two doses of the vaccine wanes, meaning their effectiveness in protecting users also declines several months later,` said Peter Hotez, a pediatrician and vaccine scientist at the Baylor College of Medicine.

Overall, studies to date show that in people who receive booster doses of all mRNA vaccines, antibody levels increase enough to prevent Omicron infection.

During the anti-epidemic meeting at the White House on December 15, Anthony Fauci, Director of the National Institute of Allergy and Infectious Diseases, commented: `Boost doses of vaccine in general can protect against Omicron. At this time, there is no need for preparation.`