Community immunity is the target that is set from the Pandemic of Covid-19, but when the world reaches this ability is still a difficult question.

Achieving community immunity will help countries with uncompromising policies with Covid-19 can open a safe border, while offices and schools in other countries are fully reopened.

However, when the new variant threatens to reduce the effectiveness of the vaccine and most of the global population cannot be vaccinated this year, many experts believe that the question reaches community immunity at any time or yes

Many policy makers attach community immunity with the time of successful translation or pandemic termination, but it depends on your definition of the end of the pandemic, Kwok Kin-on, Associate Professor

Two of the factors are the effect of the vaccine and the ability to spread the virus.

A vaccine vaccination point in Phuket tourism island, Thailand in April. Photo: Reuters.

Previous community immunity estimates are based on the first strain.

We are really thinking about much higher community immune threshold to prevent the risk of spreading the translation, she said.

Mike Ryan, director of the emergency medical program of the World Health Organization (WHO), said that threshold has not been specified, but certainly over 80% is necessary to significantly reduce the risk of infection

The implementation of Vaccine Covid-19 globally has given some suggestions on how the community immunity will like and the risks can occur.

The study announced this month in Nature Medicines, showing Israel's high immunization level, using Pfizer vaccine, which is related to a significant decline in infection in children who have not been vaccinated, showing efficiency

Another study of the Brazilian scientist group in the small city of Sao Paulo Suburbs indicates those who have not been protected before Covid-19 when 3/4 of the population, of which 95% are adults, injected

However, local government data and research results also show that despite the high rate of vaccination, the city still records new infections.

According to observers, one of the reasons is that vaccine is not perfect.

With some vaccines with an effective rate of 80%, one of five people exposed to cases will appear symptoms, Joanna Kirman, an immune house and is Associate Professor of Otago University in New Zealand, said.

In addition to the efficiency of vaccines, the appearance of variations and easing control is too fast can threaten the ability to achieve community immunity.

We will not be able to erase a pandemic for a long time in most countries, but what we do is to limit the risk of infection to a very low level, Peter Collignon, Professor Microbiology at Dai

Collignon emphasized the consequences of pandemic for humans to be less serious if the vast majority of the elderly are at high risk of vaccination.

Experts added that the Vaccine Deployment Plan and different translation control measures may cause countries to record different results and risks in the next few years.

However, the biggest barrier to gaining global community immunity is a narrow and uneven source of vaccine supply, according to experts.

Because the deployment of vaccines is still slow and translation continues to spread, future strains can buck out our results, Peter Chin-hong, medical professor at the University of California in San Francisco, USA,

Collignon said that this means that travel limited measures continue to be applied in the next few years when countries have a high vaccination rate to avoid disturbing new variants.

We vaccinate as much as we need less limited measures.