Is omicron better at evading existing vaccines than older coronavirus variants? Vaccine-makers are racing to produce omicron-specific versions, just in case. But if omicron is as transmissible as some fear, it could rapidly sweep around the world, triggering another wave of covid-19 cases before people can be protected with an updated vaccine.
mRNA vaccines can be updated more quickly than other types of vaccine, and the two main manufacturers of the covid-19 mRNA vaccines, Moderna and Pfizer/BioNTech, say they will be able to start production within the next few months. But the updated vaccines will still need to go through some tests in people before they can be rolled out more widely.
This is why authorities around the world are urging people to get vaccinated now if they haven鈥檛 already, or to get a booster shot if they have been. High levels of antibodies might provide decent enough protection against the variant, even with a less-than-perfect vaccine. This is true of the delta variant: vaccine efficacy against symptomatic infections is around 15 per cent lower with delta, but booster shots can raise it to .
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Understanding omicron
To get an idea of how good omicron is at evading existing immunity, researchers will need to test how well antibodies taken from people who have been vaccinated or previously infected work against omicron in the lab. These neutralisation tests can be done in a matter of days, but they require live samples of omicron, which are hard to come by for now.
At best, however, neutralisation tests will only give us an idea of how much more likely people are to get symptomatic infections. What we really want to know is if omicron is more transmissible and more likely to cause severe disease.
鈥淐urrent information is insufficient to determine if this variant is going to spread significantly, causing hospitalisations, and to what extent it may evade the immunity received with vaccines,鈥� says a spokesperson for the European Medicines Agency. 鈥淓MA considers it therefore premature at the moment to foresee the need for an adapted vaccine.鈥�
Updating the vaccines
No country has set out criteria for when vaccines should be updated, as far as 快猫短视频 can establish. But any decline in vaccine protection against severe disease is likely to be a key factor. This can only be established by real-world studies of people infected by omicron, which could take many weeks.
The US ,听 and UK will not require updated versions of existing covid-19 vaccines to undergo the large-scale trials to determine efficacy that were done the first time around. However, all three agencies pointed 快猫短视频 to guidelines requiring that small-scale human tests are still done to establish safety and ensure that updated vaccines produce the expected kind of immune response.
This testing could take several weeks at least, and the results will then have to be submitted and approved before vaccination can even begin. Administering the vaccine will take many more weeks. It has taken the UK to give booster shots to just , for instance.
That said, a lot will depend on the urgency of the situation.聽 If omicron isn鈥檛 much worse than delta, the vaccines might not be updated at all. So far have been fully vaccinated, and switching some capacity to making updated vaccines will slow progress on raising this number.
鈥淧roduction levels have increased substantially over the course of 2021,鈥� says at Imperial College London. 鈥淗owever, if we need to produce vaccines in parallel against omicron and another [older variant], the production capacities would be split.鈥�
If omicron is more likely to cause severe disease, this will soon become clear, and countries may expedite the roll-out of updated vaccines.
