The German company CureVac announced on Friday that its vaccine against Covid-19 had passed its first interim analysis but was not yet ready to share data on how well it protects against infections. The shot could be cheaper and more accessible to low-income countries lacking vaccines.

The company said 59 volunteers had developed Covid-19 and that their data safety monitoring board had not identified any safety concerns. However, the board did not share any data on effectiveness, suggesting that it is not yet clear how much protection the vaccine offers.

“The study will continue to collect enough data to conduct a statistically significant effectiveness analysis,” the company said in its statement.

The vaccine is based on mRNA technology as developed by Moderna and Pfizer-BioNTech. These vaccines are used in the US and the European Union and have been shown to be extremely effective, increasing the chances that CureVacs could also offer strong protection against the coronavirus.

CureVac may have several advantages over the other mRNA vaccines. It can be stored in the refrigerator at 41 degrees Fahrenheit for at least three months, and it can stand at room temperature for 24 hours before being used.

In their original formulations, the Moderna and Pfizer-BioNTech vaccines had to be frozen. Both companies have tinkered with their recipes to make their vaccines more stable in warmer temperatures, which can expand their use in poorer countries where freezing can be a challenge.

CureVac can also turn out to be cheaper than its potential competitors. Public Citizen, a consumer protection organization, published a report by researchers at Imperial College London on Wednesday that estimated how much it would cost to make enough RNA vaccines to ensure herd immunity in low and middle income countries. It would cost $ 22.83 billion to make 8 billion doses of Pfizer-BioNTech, $ 22.43 billion for Moderna, and just $ 4.38 billion to make CureVac.

Last year the company had promising results with its animal vaccines. By December, they had started their final clinical study and recruited 40,000 volunteers in 10 countries in Latin America and Europe.

The study was designed so that an external panel of experts would regularly review the study data while some volunteers were developing Covid-19. They would be looking for warning signs that the vaccine wasn’t safe. They would also check how many of the sick volunteers got the CureVac vaccine and how many got a placebo. If the placebo group were much larger than the vaccine group, it would indicate the Covid-19 protected vaccine.

It is impossible to say exactly when CureVac will hit enough cases to show its final results. However, on Wednesday the company said it should have results before the end of June. “We expect the data from the crucial phase 2b / 3 study to be read out in the second quarter,” says an update.