Scientific Committees under CHP publish consensus interim recommendations on the use of COVID-19 vaccines
During the meeting, published data of vaccines undergoing phase four clinical studies were examined. It was noted that the effectiveness of the vaccines against symptomatic COVID-19 cases in real life situation is comparable to the findings in phase three trials and they are also found effective against COVID-19 related hospitalisations and deaths. Rapid deployment of the vaccines should be enabled to achieve a high level of coverage as soon as practicable.
Recommendation of COVID-19 vaccination for those with previous COVID-19 infection was discussed in the meeting. Previous COVID-19 infection usually confers immunity for at least six to nine months for majority of patients. There is accumulating evidence showing that those previously infected with COVID-19 would be further protected by one dose of mRNA vaccines. After receiving one dose of mRNA vaccine, these persons may experience more systemic side effects, such as fatigue, headache, chills, muscle pain, fever and joint pain, when compared to those without prior infection. People who wish to receive mRNA vaccine should wait for at least 90 days after discharge from previous infection. There is currently no data on the role of inactivated vaccines.
Emerging variants are constant threats to the protection conferred by COVID-19 vaccines. The meeting also discussed the existing evidence on COVID-19 vaccine effectiveness against different variants. There were several variants circulating globally, including the variants first emerged in the United Kingdom (B.1.1.7), in the South Africa (B.1.351) and in Brazil (P.1). In general, studies have shown that the existing vaccines works well against the non-variant. The effectiveness data against variants differ by vaccines. The Fosun Pharma/BioNTech vaccine (BNT162b2) is effective against B.1.1.7 and P.1, but is less effective against B.1.351. There is currently limited efficacy data of CoronaVac developed by Sinovac Biotech (Hong Kong) Limited against variants. The company is currently implementing a large scale study in Brazil and more efficacy data against variants will be available. The vaccine developed by AstraZeneca, in collaboration with the University of Oxford (AZD1222) is effective against B.1.1.7 but is ineffective against the B.1.351 variant. Achieving a high COVID-19 vaccination coverage as soon as possible and continuing robust non-pharmeutical interventions to minimise the chance of viral transmission would be a priority goal in controlling the epidemic and preventing the emergence of variants.
The meeting also deliberated the impact of vaccine delivery on the public health strategy of non-pharmaceutical interventions (NPIs) and considered that at the current phase of the vaccination programme there is some preliminary evidence on the effects of vaccination on preventing transmission and challenges posed by the emergence of COVID-19 variants.
The World Health Organization and European Centre for Disease Prevention and Control consider that proof of vaccination should not cause international travellers to be exempted from complying with travel risk reduction measures.
Hong Kong has a very stringent testing and quarantine requirement for inbound travellers. From December 2020 till mid-March 2021, among the over 400 imported cases reported in Hong Kong, about four per cent were detected beyond 14 days of quarantine. Among these imported cases, over 90 cases were detected to have variant strains, of which, more than 60 per cent were asymptomatic at the time of specimen collection. It is essential to maintain the current testing and quarantine measures.
The meeting agreed that the combination of NPIs with vaccination will allow for maximum protection against the virus. There is a need to continue public health strategies on NPIs, including social distancing, good hand hygiene and wearing a mask in public, to reduce the risk of transmission.
NPIs should continue to be followed by vaccinated individuals, as well as those who have not yet been vaccinated. Any changes to NPIs should be carefully monitored, but can be reviewed with increasing vaccination coverage.
Details of the interim recommendation are available at CHP website www.chp.gov.hk/en/static/24008.html.
Ends/Thursday, March 18, 2021
Issued at HKT 23:59
Issued at HKT 23:59