Pfizer partner BioNTech aims to begin tests this month to determine if an altered form of its COVID-19 vaccine can better protect against the far more contagious Delta variant.

The clinical trial, whose results are anticipated in the fourth quarter, will also examine whether a combination of jabs that includes an inoculation against Delta and the original “wild type” proves effective.

Should the data confirm the desired antibody response, BioNTech expects it can adapt production within 100 days. Since the same raw materials and factory equipment are employed, all it needs to do is swap out the DNA template to account for a different genetic sequence in the spike protein.

For now, however, the German biotech firm recommends a third booster shot of the existing vaccine. Studies indicate that the current vaccines are still highly effective in preventing hospitalizations and deaths from COVID-19 variants like Delta.

“We believe the best approach at the moment to deal with the situation is to continue with a booster dose with the existing wild type strain,” chief executive Uğur Şahin told investors on Monday during a quarterly earnings call, citing evidence that it already proved effective against the Beta variant first discovered in South Africa.

Rival vaccine maker Moderna, which also uses messenger RNA to produce antibodies, likewise recommends a third vaccination. There are also trials underway on the effectiveness of mixing and matching vaccines for boosters. However, the World Health Organization recently called for a moratorium on booster shots, to allow poorer nations to catch up on vaccines.

Shares in BioNTech, the first company worldwide to develop an effective inoculation against the coronavirus, surged 14% to €442.71 after it reported that its net income for the first half swung to €3.9 billion ($4.6 billion) from a loss of €142 million a year earlier.

Revenue surged more than 100-fold to €7.4 billion primarily thanks to payments from partner Pfizer, which distributes the vaccine it created to most parts of the world. Earlier this month reports emerged that the U.S. drugmaker would raise the price of the BioNTech vaccine for Europe.

BioNTech itself markets its own treatment directly only in Germany and Turkey, the adopted and native homes respectively of the husband-and-wife pair that founded the company.

Together with global distributor partners Pfizer and Fosun, BioNTech expects to ship 3 billion doses this year and 4 billion in the next.

It has committed to delivering over 2 billion doses to low- and middle-income nations over the next 18 months.