Dr Paul Burton, Moderna's chief medical officer, warned of a new super-variant

Moderna’s Chief Medical Officer Dr Paul Burton warned about a super-variant

A new super-variant could be created if Omicron and Delta infect someone at the same time, a Moderna boss has warned.

Covid infections normally only involve one mutant strain, but in rare cases two — likely from different sources — can infect a person at the same time.

They may also be capable of swapping DNA, making a new form of the virus.

The chief medical officer at the vaccine maker, Dr Paul Burton, said that this was more likely because of the number of Omicron- and Delta-cases currently in Britain.

The Science and Technology Committee was informed by him that they were able to swap genes and create a more deadly variant. 

Scientists have cautioned that such events, also known scientifically as’recombination event’, can occur but require specific conditions and the simultaneous appearance of many uncontrollable factors.

There have been only three Covid mutations caused by virus swapping genes. This is because the virus rely on random mutations to create more strains.

Over the period of two months, when Alpha strain outcompeted Delta via this method, a new variant wasn’t triggered.

Omicron has already been spotted in London only two weeks ago. Experts believe it will become the dominant strain in London by next year.



Dr Burton explained to the Commons how the possibility of the variants being able to circulate together increased the chance that they would swap genes or create a new one.

He said: ‘There’s certainly data, there have been some papers published again from South Africa earlier from the pandemic when people — and certainly immunocompromised people — can harbour both viruses.

“That’d be feasible here given how many infections we had been seeing.”


For a combined variant of the virus to emerge, one person must be infected with two strains of the coronavirus – likely from two separate sources – at the same time, and then the viruses must bump into each other inside the body. 

Once viruses have been infected, they can spread by forcing cells to produce more. 

Coronaviruses contain genetic material, called RNA. In order to reproduce, they must force their bodies to recognize this RNA, and then make precise copies.

This is a fast-paced, often occurring event and the natural process of things can make mistakes. 

When two viruses find themselves in the same location at the same moment, each being replicated by identical cells, the chances are that the RNA gene could get mixed up. It is similar to a person dropping two sets of cards and picking them up all at once.

Many places are home to dominant strains of the virus, so it’s unlikely someone can get infected by two. 

Healthy people will have a two-week window before their bodies develop immunity and clear the virus. 

This risk window could be cut to days for the majority of people who develop Covid symptoms  – which takes an average of five days – and then stay at home sick.

However, large, uncontrolled outbreaks such as those in the UK or US during the winter can significantly increase the likelihood of the combined events, simply because there are more infections. 

He said that this might lead to an even more dangerous version.

It is very unlikely that you will be infected by two different strains of the virus at once as most places contain dominant versions.

For healthy individuals, the time frame for triggering an infection is only two weeks before the body develops immunity to the second version.

For most people with Covid symptoms, their risk window may be reduced to just days because they need to isolate.

But, large and uncontrolled epidemics such as those in the UK or US this winter can increase the likelihood of recombination events because of the higher number of infections.

Britain has currently confirmed 4,713 Omicron cases. The variant accounts for approximately one fifth of the cases nationwide. 

Delta has four out of ten cases currently, but that number is falling.

MailOnline was told by scientists that although it may be possible for the viruses to swap genes between themselves, this is unlikely.

Two other mergings have triggered three variations.

However, none of these have resulted in a widespread outbreak or an even more serious version.

A recombination occurred in one instance in the UK. The Alpha variant of the genome merged with B.1.177 in B.1.177’s first appearance in Spain in February.

This led to the creation of 44 additional cases that eventually disappeared.

California scientists claimed that they have identified another variant of recombination in February. The Kent strain merged with B.1.429, which was the first to be spotted in this area.

Also, this new strain led to very few cases and was soon extinct.

Covid mainly relies on random mutations in order to create new variants.

These errors occur because the virus creates copies of itself and its genes are altered.

These changes in most cases are not harmful, but they may cause an advantage like being more transmittable or better able evade vaccinations.

Omicron was believed to have evolved from an infected person with immunocompromised. The virus was able to evolve several times in order to become more effective at infecting people and to avoid immunity.