Since the Omicron variant appeared, many countries around the world are witnessing a rapidly increasing trend of infections, including countries with high vaccination rates.

`Over time, the protection of two doses of the vaccine begins to wane, while the third dose helps strengthen protection again, with effectiveness against symptomatic infection reaching more than 90%,` Prime Minister Nguyen Xuan Phuc said.

Israel is the pioneer country in implementing the booster vaccination program since the end of July, with the first subjects being the group over 60 years old who have been vaccinated with the second dose for 5 months.

On August 29, Israel began giving booster vaccines to all people aged 12 and over.

Despite initial doubts about the necessity of the booster shot, after more than three months of implementation, Israeli health officials say the data collected proves the booster vaccination program helps curb the pandemic wave.

Israeli officials said the effectiveness of the booster shot is clearly shown in the number of hospitalizations.

Recent studies also show that the booster vaccine is an effective anti-epidemic `weapon`, in the context of the Omicron strain causing concerns about the risk of overtaking Delta to become the dominant strain globally.

A man received a booster shot of the Covid-19 vaccine in Tel Aviv, Israel, on August 30.

According to analysis results published on December 18 by a research team at Imperial College London, one of the oldest and most prestigious universities in England, the booster shot has the potential to achieve an effectiveness of 80-85.9

This rate is slightly lower than the boosted vaccine’s ability to prevent severe cases with previous strains, but will still keep many people out of the hospital.

Lessons from Israel, along with the skyrocketing number of nCoV infections in Europe and the US, have prompted governments to urgently deploy booster vaccinations.

He currently gives booster shots to all adults, three months after the second dose.

The UK shortened the booster injection time after an assessment by the European Medicines Agency (EMA).

On November 24, the European Center for Disease Prevention and Control (ECDC) also recommended booster vaccination for the entire adult population, prioritizing people over 40 years old, instead of just elderly people with good health.

Similar to the UK, many European countries are implementing booster vaccinations for all adults such as Germany, France, Austria, and Greece.

On November 30, the US Centers for Disease Control and Prevention (CDC) called on all people over 18 years old to get booster shots to cope with the Omicron mutation.

Unlike the above countries, many countries are not currently giving booster shots on a large scale, but only giving additional doses to people with weak immune systems, the elderly or vulnerable people, similar to the recommendations of the World Health Organization.

WHO believes that enhanced vaccination programs in countries need to focus on groups of people with weak immune systems to avoid causing vaccine inequality.

Some European countries are applying this policy, including Bulgaria, Denmark, Finland, Portugal or Spain.

In Asia, Japan just started giving booster shots to medical staff at the beginning of the month, and is expected to vaccinate the elderly from January 2022, with a gap between two doses of 6 months.

Indonesia initially planned to have booster shots after reaching the goal of at least 70% of the eligible population receiving at least one vaccine shot and 50% receiving two doses.

Indonesia has just deployed booster shots for medical staff, but this program will be widely implemented from early next year, with priority given to immunocompromised people and the elderly.

Some other Southeast Asian countries show more urgency than Indonesia.

Meanwhile in China, many provinces and cities began booster shots in October, as more and more data showed that immunity from inactivated vaccines used in the country was declining.

However, booster vaccination regulations in China vary between provinces and cities.

In other places, such as Hebei and Sichuan provinces, the elderly and high-risk groups are given priority, but authorities say those who need them will be vaccinated.

Regarding the type of vaccine used for the booster shot, the US Food and Drug Administration (FDA) approved the third injection of Pfizer and Moderna vaccines for all adults on November 19.

American pharmaceutical company Pfizer and German partner BioNTech said their booster vaccine is still effective against the Omicron variant.

Most countries that are implementing enhanced vaccination programs use two types of vaccines developed using this mRNA technology.

According to recent research on the safety and immune response of booster shots, published in the journal Lancet on December 2, most Covid-19 vaccines are safe to use as booster doses and to provide