Pfizer and BioNTech will begin trials of their updated mRNA Covid-19 vaccine designed to protect against the newer BA.4 and BA.5 sub-variants of the coronavirus latest this month, BioNTech announced on Monday, joining other vaccine makers like Moderna who are trying to create updated shots targeting the faster spreading and immune evasive variants.

The trial announcement was included in BioNTech’s financial results for the second quarter of 2022.

BioNTech and its American partner Pfizer have started manufacturing “bivalent” Omicron BA.1 and BA.4/BA.5 vaccines that will offer protections both against the fast spreading newer variants and earlier variants, the company said.

The company claims it will be able roll out the updated shots by October—in time for potential fall boosters—if it receives regulatory approval.

Pfizer and BioNTech have already carried out clinical trials for their BA.1 Omicron-focussed vaccine—it was shown to produce higher neutralizing antibodies against the variant—and have submitted the findings to regulators.

As per the Food and Drug Administration (FDA), vaccine makers do not need to submit updated clinical trial data for the BA.4/BA.5 adapted shots. The agency will instead approve the modified vaccines using clinical data from the BA.1 vaccine trials. This will allow the updated vaccines to be approved quicker. However, the European Medicines Agency has said it doesn’t intend to follow the path of its American counterpart and will instead require vaccine makers to submit clinical data for each of the new updated shots.

In June, the FDA issued an advisory asking vaccine manufacturers to modify their booster shots to retain their current composition—to prevent serious Covid-19 illness—while adding an omicron BA.4/BA.5 spike protein component to help curb the spread of the highly infectious variants. Moderna, which makes the other widely used mRNA Covid-19 vaccine, announced in July that it had trialed a bivalent booster that produced higher neutralizing antibodies against the BA.1 and BA.4/BA.5 sub variants. Despite these developments an Omicron specific booster is yet to be approved anywhere and there are concerns that vaccine makers may always be left playing catch-up against the coronavirus which continues to spread and potentially mutate further.