Filenews 3 May 2021
By Sam Fazeli
Britain has been a kind of "renegade" in its anti-covid-19 vaccination programme. At the start of the global campaign, the UK - in an effort to vaccinate as many people as possible as soon as possible - lengthened the period between the 1st and 2nd instalments longer than the trials indicated until then.
Instead of the proposed three-week "distance" between the two doses of the Pfizer/BioNTech vaccine or the 6 to 12 weeks for the vaccine jointly developed by AstraZeneca and Oxford University, the UK government set the interval at 12 weeks for all vaccines. It was a risky bet that was criticised by both health experts and analysts (among them myself), as they worried that this move (which had not been "tested") would weaken protection against the virus and "give space" to mutant strains.
Fortunately, the bet paid off: The vaccination campaign went extremely well. This was partly contributed by the simultaneous 4-month "hard" lockdown, which resulted in a decline in infection numbers and a reduced risk of developing mutations that would be more resistant to vaccines. Turns out I was wrong to worry about the government's approach. We should give credit to Britain's scientists and policymakers, having managed to reach very low numbers of new infections, despite the gradual relaxation of restrictive measures.
During this period, however, the United Kingdom is being "diverted" again. In a way that poses new risks. And this time, officials may not be properly assessing the risk.
The UK restricts the use of the AstraZeneca vaccine to a small extent, recommending that people under 30 do not have it. This is the youngest age group in which this recommendation is made, compared to other western European countries, although potentially the highest rate of rare cases of thrombosis (now called thrombosis with thrombocytopenia syndrome or TTS) occurs in younger people. All these countries have access to the same data on the incidence rates of rare clots and can make the same calculations when called upon to rule on the risk-benefit balance. So who's right? I think they're both wrong.
In assessing the risk-benefit balance of vaccines, the history of the number of infections should be taken into account, as this element is vital to see whether the risks of side effects outweigh the risk of someone getting sick. When there is a higher number of infections, the risk of someone becoming seriously ill from covid-19 increases accordingly, and this may be an argument in favour of the lower risk that there is potentially from the side effects of the vaccine. When the numbers of cases move at low levels and the risks are not heterogeneous, the opposite is the case. That is the crux of the matter.
Both the UK Medicines and Health Products Regulatory Agency (MERA) and the European Medicines Agency (EMA) have published infographics showing this interaction. With infection numbers moving at low levels, as currently in the UK, the MHRA points out that cases of rare clots associated with receiving the vaccine amount to 0.8 per 100,000 people for the 30-39 age group, at the same time as 2.7 per 100,000 people are admitted to ICU covid. Of course, there's a difference. But it's not as big as the one we notice when the numbers of infections move higher. In several European countries, imports into ICU covid are 24.9 per 100,000 people.
Given the low number of cases, the UK is taking too much risk with the AstraZeneca vaccine. It should raise the age limit to 55 years and above, where the risk of thrombosis is 0.4 incidents per 100,000 people and the risk of admission to ICU covid amounts to 10.5 cases per 100,000 people. And it will have to do so, even if it means delaying the resumption of certain activities because of the restrictive measures.
On the other hand, EU countries make the mistake of administering the vaccine only to people over the age of 55 or 60, given that relatively high numbers of cases and deaths occur throughout the European bloc. Although the EU is not fully dependent on the AstraZeneca vaccine, this formulation remains an important "weapon" in the armour to fight the pandemic and prevent many deaths.
Of course, all this pales in the face of the tragic situation unfolding in India. There, even one dose more tilts the risk-benefit balance in favour of the vaccine. After all, the battle against covid-19 is taking place all over the world. Even in countries or regions where case numbers are declining, an appropriate response (assessing the risk-benefit balance based on local health conditions) is vital to keep things on track and reduce losses.
Source: BloombergOpinion
