Data on Severity of Illness Experienced by COVID-19 Vaccinated Patients and Evaluation of Effectiveness of Vaccines for Booster Jabs
Ministry of HealthSpeakers
Summary
This question concerns the comparative effectiveness of COVID-19 vaccines and data regarding severe illness or death among vaccinated individuals. Several Members of Parliament requested breakdowns of medical outcomes by vaccine type and details on booster shot policies. Minister for Health Ong Ye Kung responded that mRNA vaccines provide 90% protection against severe disease, showing significantly lower mortality rates compared to unvaccinated persons. He explained that while local data for non-mRNA vaccines is limited, international studies suggest mRNA vaccines offer higher protection against symptomatic infection. Minister for Health Ong Ye Kung noted that mRNA boosters provide the strongest protection and that severe adverse event rates are similar across vaccine types.
Transcript
29 Mr Yip Hon Weng asked the Minister for Health amongst the vaccinated patients in Singapore who (i) required ICU stay or (ii) died respectively, how many got a mRNA vaccine and how many had a non-mRNA vaccine.
30 Mr Cheng Hsing Yao asked the Minister for Health (a) of the vaccinated COVID-19 patients who have developed serious symptoms, how are they distributed across the different vaccines; and (b) whether there is data that suggests which vaccines are more effective in preventing the development of serious COVID-19 symptoms.
31 Mr Dennis Tan Lip Fong asked the Minister for Health whether the Government will allow people to choose a different vaccine, including a non-mRNA one, for their COVID-19 booster shots.
32 Mr Gerald Giam Yean Song asked the Minister for Health regarding all the COVID-19 vaccines approved for use in Singapore, including those available under the Special Access Route, what is the effectiveness, based on real-world data in Singapore or elsewhere, against the Delta variant for each of these vaccines against (i) infection (ii) symptomatic infection (iii) severe infection requiring oxygen supplementation and/or ICU care (iv) death and (v) transmission.
33 Mr Leon Perera asked the Minister for Health (a) of the deaths of fully vaccinated persons from COVID-19, what is the breakdown by vaccine type; and (b) what is the number of breakthrough COVID-19 deaths per 10,000 fully vaccinated persons for each vaccine type.
34 Mr Zhulkarnain Abdul Rahim asked the Minister for Health whether the Ministry or the Expert Committee on COVID-19 Vaccination (EC19V) has studied the research on the effects of using different vaccines for the initial and booster doses and the efficacy of taking different booster vaccines.
Mr Ong Ye Kung: Members are interested to know how different COVID-19 vaccines compare in terms of their protection. As we roll out our vaccination and booster programmes, MOH and HSA have continued to collate and analyse data on the effectiveness and safety for different vaccines. The following are what we have found out so far.
First, there is a big difference between being vaccinated and not vaccinated. Between 1 May 2021 to 30 September 2021, the COVID-19 mortality rate was 7.5 per million persons among those vaccinated with the two mRNA vaccines. In contrast, the mortality rate among those who were unvaccinated or partially vaccinated was 92 per million persons. In the same period, the risk of severe disease, including the need for intensive care and/or oxygen supplementation, was 86 per million persons for those vaccinated with the two mRNA vaccines, and around 530 per million persons for those who were unvaccinated or partially vaccinated.
Second, both mRNA vaccines in our National Vaccination Programme work very well. Both mRNA vaccines protected infected persons against severe disease by around 90%. The mRNA vaccines also reduced the risk of infection by around 40% and halved the risk of onward transmission.
However, a comparison with the non-mRNA vaccines cannot be made at this time, as the number of persons vaccinated with them is much smaller. Less than 2% of the population was fully vaccinated with Sinovac-CoronaVac as of 30 September 2021. Further, in Singapore, a very small proportion of seniors aged 60 years and above chose to be vaccinated with Sinovac-CoronaVac, as the take-up has been mostly in younger people. In a recent study in Chile, Sinovac-CoronaVac was found to confer 58% protection against symptomatic infection compared to 88% for Pfizer. The corresponding figures for protection against severe illness requiring ICU care were 90% and 98% respectively.
Current evidence shows that persons vaccinated and boosted with the PSAR-authorised mRNA vaccines develop the strongest boosting in antibody levels and protection against infection and severe disease, compared to other COVID-19 vaccines.
The Health Sciences Authority (HSA) closely monitors the safety of the COVID-19 vaccines. As of 18 October 2021, the rates of reported Severe Adverse Events for Sinovac-CoronaVac and the mRNA vaccines were similar, at around 0.005%. Management of adverse events from vaccines, as with other conditions, is evidence-based and takes into consideration local and international data as well as the patient’s medical condition.