- The study had been conducted prior to the release of real-world data from immunisation programmes and how it affected the spread of the virus
- The modelling was conducted keeping in mind the manner in which the UK’s current vaccination rollout will dovetail with easing control restrictions in different scenarios
- Four scenarios one where vaccine protection against infection stood at 0 per cent, another at 35 per cent, the third at 60 per cent, and the fourth at 85 per cent were modelled
A new study conducted by researchers in the United Kingdom and published in The Lancet Infectious Diseases Journal has shed new light on the extent to which vaccination programmes may be able to curb the spread of the COVID-19 virus.
Having approved one or more of the various vaccines developed, countries across the world have commenced their immunisation rollouts premised on a notion that vaccinating enough of a population within a specific geographic area may be enough to drive down COVID-19’s reproduction number (R-naught) to a point where the virus, having increasingly fewer vectors to move across, will eventually be stamped out.
However, the latest study has indicated that vaccinating all adults alone in the UK is unlikely to completely curb the spread of the virus. It further stated that a slow and gradual release of containment measures, rising vaccination rates, and the use of a vaccine with high efficacy are vital to reduce the risk of future waves of infection.
There are some important caveats to mention though. Firstly, the study had been conducted prior to the release of real-world data from immunisation programmes and how it affected the spread of the virus. According to preliminary findings, vaccination has been found to provide some degree of overall protection against infection, however, to what extent remains unclear.
Secondly, the study also does not account for the emergence of new variants of COVID-19 observed across the UK and the world and how this may affect vaccine efficacy. It also did not take into account the waning effects of immunity proferred by vaccines – crucial research that can only be undertaken in the months ahead.
Finally, the authors also concede that they have not been able to isolate the effect of relaxing any one individual control measure.
What did the study say?
The modelling was conducted keeping in mind the manner in which the UK’s current vaccination rollout will dovetail with easing control restrictions in different scenarios, towards identifying how this affected the virus’ R-naught, the number of hospital admissions and the number of deaths, between January 2021 and January 2024.
The model assumed that 95 per cent of those aged 80 or older were vaccinated, along with 85 per cent of those aged between 50 and 79, and those aged between 18 and 49. Phase 3 trial data from Pfizer-BioNTech and AstraZeneca-Oxford University was used to arrive at an 88 per cent vaccine protection against symptomatic infection.
Four scenarios – one where vaccine protection against infection stood at 0 per cent, another at 35 per cent, the third at 60 per cent, and the fourth at 85 per cent – were modelled.
The crux of the study relayed that, while vaccination will play some part in reducing the R-naught figure, it will not be effective enough to drive it below 1. In the best-case scenario (85 per cent protection), the R-naught remained as high as 1.58, in the absence of any other control measures.
As such, the authors predicted that the removal of all restrictions could very well lead to a resurgence of the virus, another wave of infections, and consequently, more deaths.
The extent of the death toll hinged on how gradually containment measures were relaxed, the level of vaccine uptake and the protection that vaccines provided.
The authors predicted that rolling back containment measures in February 2021 would lead to 131,100 coronavirus deaths in the country by January 2024. If measures were partially eased in April 2021, this would lead to an estimated 61,400 deaths by 2024. Removing restrictions in June 2021 would result in 53,900 deaths. Finally, if all lockdown measures were terminated in January 2022 after the full vaccine rollout was completed, the authors predicted a total death toll of 21,400.