Seven-day quarantine for fully vaccinated foreigners feasible: experts

By Viet Anh   June 10, 2021 | 05:02 am PT
Vietnam can prescribe a shorter than usual quarantine period for fully vaccinated people entering the country, with some attached conditions, foreign experts say.

Early this month, Vietnam's health ministry had said fully vaccinated people entering Vietnam and test negative for the novel coronavirus may see their quarantine period reduced from 21 days to one week.

The possibility of a reduced quarantine period finds agreement from Harry Severance, Adjunct Assistant Professor, Duke University School of Medicine, the U.S.

"I would agree on a reduction to 7 days," he said.

Severance explained that a rising number of studies show that fully vaccinated persons have a very low likelihood of getting infected or re-infected with Covid-19, and therefore the chances of infecting others in general conditions (avoiding intimate/close contact) are also minimal.

The few persons who are re-infected post vaccination are "generally" minimally ill. More importantly, they have not demonstrated the ability to transmit their re-infection to others, except by intimate or extremely close contact, Severance said.

Therefore, it is viable that quarantine preference is given to those who are both successfully vaccinated and have tested negative for the virus, because they represent a high degree of safety, he added.

He also noted that the vaccines studied were those recognized by reputed agencies such as the World Health Organization (WHO) and the European Union (EU).

Health workers in a quarantine centre in HCMC, May 2021. Photo by VnExpress/Huu Khoa.

Health workers in a quarantine center in HCMC, May 2021. Photo by VnExpress/Huu Khoa.

Furthermore, Severance suggested if there was continued success in disease prevention under the proposed guidelines, the government could even consider waiving quarantine for this group, who have been vaccinated and tested negative, if they agree on contact tracing of their activities while traveling.

He observed that many countries and venues are now opening up to tourists who have documented proof of their vaccinations (with or without acute testing) with no quarantine or tracing.

However, he stressed that every country must develop its own "level of comfort" in addressing pandemic-related issues.

Additional conditions

While he agreed with the shorter seven-day quarantine, Professor Edward Trapido, Louisiana State University School of Public Health, the U.S., said it should be implemented with several additional conditions.

For instance, authorities should make sure that a person coming to Vietnam has had the correct number of doses of their vaccine (some require one, others require two) and the date of the last dose is at least two weeks before entering Vietnam.

"This time period allows complete immunity to develop," he said, without mentioning a maximum efficacy period or follow up measure.

In case a quarantined individual tests negative after five days, he or she can be allowed to leave the quarantine facility after seven days. If an individual is not tested during the quarantine period, he or she should stay in quarantine for 10 days, Trapido said.

He also said that though the variant circulating in Vietnam seems to be very contagious, combining some of the traits of the variant found in India and in the United Kingdom, he believed most current vaccines work well against this variant. This means that fully vaccinated individuals will be unlikely to get the infection, if they do, their viral load will likely be low and they are unlikely to be able to spread the infection, Trapido said.

Adding conditions for seven-day quarantine, Dicky Budiman, an epidemiologist with the Griffith University Australia, said vaccinated people coming to Vietnam should visit "within three months of getting their second shots" because scientists still don’t know "if the antibody or the protection is still there or not."

For example, a person who gets the second jab in June can have a seven-day quarantine if she or he comes to Vietnam by September. If the person enters Vietnam in October, she or he must be quarantined for 14 days, he said.

Budiman also noted that authorities should be careful in allowing people to go in for short quarantine periods based on their departure. In some countries, individuals may not have had symptoms and they need to be tested using whole genome sequencing to identify the variant, if any. In other words, health workers should closely follow people's symptoms and do regular tests, he added.

In the U.K., Professor Adam Finn with the University of Bristol expressed concerns over the new move, saying he'd like to see evidence that unvaccinated people can remain infectious for up to 21 days and vaccinated people who become infected have a reduced viral shedding duration of seven days.

"Perhaps such evidence exists but I’m not aware of it," Finn said.

Professor Sharon Lewin, director of the Peter Doherty Institute for Infection and Immunity (PDI) in Australia, joined the majority of experts in supporting seven-day quarantine. She said it is a reasonable strategy that accounts for reduced risk of infection post vaccination. The PDI was established by the University of Melbourne and The Royal Melbourne Hospital.

Lewin said that the chance of becoming Covid-19 infected in the second week of quarantine was greatly reduced compared to the first. This chance is even further reduced in people who are vaccinated.

"Therefore, a seven-day quarantine is a pragmatic approach."

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