7 Jun 2021

Could the social distancing measures be relaxed after vaccination?

7 Jun 2021

Professor Wong Yeung Shan, Samuel, the Director of The Jockey Club School of Public Health and Primary Care from CUHK

The pandemic has been continuing and emergence of virus variants make people panic. The most concerning issue will be the long-term efficacy of COVID-19 vaccines. Can we resume ordinary life after getting vaccinated? Let Professor Wong Yeung Shan, Samuel, the Director of The Jockey Club School of Public Health and Primary Care from the Chinese University of Hong Kong explain this issue.


Q: Can social distancing measures be relaxed after vaccination?

A: Vaccination is an effective way to control the pandemic in the long term.

As of 1 June, over 60% of people in Israel and nearly 60% of people in the United Kingdom (UK) have already taken the vaccines. UK has also announced a “Green List” of countries, travelers returning from these countries no longer have to be quarantined upon arrival. 

There is also more and more evidence supporting the efficacy of the vaccines. According to the latest scientific data, the protection rate given by the Comirnaty vaccine to people aged 16 and above is over 90%, including both infections with and without symptoms. The vaccine could even block the transmission chain among household members. Inferring from that, vaccination should be effective in reducing the infection risk in catering locations and other environments. 

It is observed locally and overseas that once the disease prevention measures are relaxed, the number of cases might rebound. From a scientific perspective, the risk of relaxing prevention measures is lower if citizens have received vaccination. Yet, successful implementation of relaxed measures, for instance in food premises, depends on the size of restaurant, the level of interaction between customers and staff across different zones in the restaurant, as well as the acceptance of the measures by citizens.

Nevertheless, the degree of relaxation depends on the proportion of the population vaccinated. Despite the high protection efficacy of the vaccines, they are not a 100% prevention measure. Still, we have to wear masks and be aware of social distancing until herd immunity is reached.  


Q: How is the response of citizens towards getting vaccinated? How far is Hong Kong from herd immunity and normal life? 

A: As of June 1, the vaccination rate in Hong Kong was just over 20%. According to the latest study conducted by CU Medicine, there is “vaccine hesitancy” in Hong Kong. During the most serious period of the third wave of outbreak last year, there were only 48% of people willing to take the vaccination. The percentage dropped to less than 40% by the end of the third wave. It further fell to 30% at the fourth wave. Only 8% of respondents answered they would “absolutely take the vaccines” during the fourth wave.

Taking reference from previous waves of the outbreak, the local immediate transmission rate has ranged from two to four; that means each patient can infect two to four people. Therefore, if Hong Kong wants to gain herd immunity, the vaccination rate must reach 50% to 75% of the population.

Due to vaccine hesitancy, we predict that herd immunity will not be reached within a short period of time in Hong Kong. Hence, social distancing measures need to be retained for a certain or even a long period of time.


Q: The coronavirus variants are spreading within the community. Does it affect the efficacy of the vaccines? Is it necessary to tighten the social distancing measures?

A: The virus variants found in the community have a higher transmission rate. We currently do not know their impact on the local immediate transmission rate. If each patient can infect more people, a higher vaccination rate is needed for the control of transmission.

Judging from the current vaccination rate and the public response, it is possible that we will be facing another wave of outbreak on an even larger scale than before in Hong Kong, hence we must be more cautious.

As for social distancing and infection control measures, a study from CU Medicine shows that Hong Kong citizens have a high awareness of wearing masks and maintaining hand hygiene. More than 95% of respondents have been practicing these since the start of the pandemic. However, the public’s attitude towards the infection has changed with time. More and more people do not regard the infection as a serious matter, and many of them are tired of fighting against the coronavirus making them less motivated in following the regulations. 


Q: Some people may worry that their health condition making them not suitable for vaccination. Which group of people should seek a doctor’s advice before receiving vaccination?

A: It is understandable that the public are concerned about the safety of the vaccines, especially since the COVID-19 vaccines have taken only a short time from development to emergency use. Yet hundreds of millions of doses have been given worldwide and data shows that the majority are suitable for the vaccination. People with a history of allergies may need to undergo an allergy test to assess their suitability for vaccination, including those who have had anaphylaxis or severe allergic reactions upon exposure to other allergens, or those who are allergic to more than one type of drug.

Currently, the Department of Health recommends that patients who have acute diseases and are receiving treatment or who have just changed medicine may have to postpone the vaccination schedule after assessment by a doctor. As for people with stable control of chronic diseases, they can get vaccinated.

Some patients with chronic diseases might develop different responses towards the vaccines. They should seek medical advice first. Immunocompromised patients, including organ transplant recipients and cancer patients should get vaccinated at least two to four weeks before receiving the surgery or chemotherapy. If patients are receiving immunocompromised treatments, they are advised to get vaccinated half a year after the completion of treatment. People taking an anticoagulant can also receive the vaccination. They should put pressure on the injection spot for at least five minutes to reduce bleeding and bruises.

If the above-mentioned people work in  designated premises like restaurants and  have to get vaccinated for a re-opening or relaxation of social distancing measures within the premises, they might need to discuss with doctors their suitability for vaccination and possible exemption. 

Professor Wong Yeung Shan, Samuel, the Director of The Jockey Club School of Public Health and Primary Care from CUHK

Professor Wong Yeung Shan, Samuel, the Director of The Jockey Club School of Public Health and Primary Care from CUHK


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