CureVac (NASDAQ:CVAC) is trailing the leaders in the race to develop a vaccine that can protect people from developing COVID-19. But the biotech is making progress, and now has data from an early-stage  trial of its coronavirus vaccine candidate that shows the top dose it's administering appears to be having the desired effect.

In the phase 1 study of CureVac's vaccine, dubbed CvnCoV, patients who were given the highest dose being tested developed neutralizing antibodies at the same levels seen in patients who had recovered from COVID-19. Neutralizing antibodies are able to bind to the coronavirus and block it from infecting a host's cells.

Nobody in the small 250-person study suffered any serious side effects. At the highest dose tested, some participants developed fatigue, headache, chills, muscle pain, and to a lesser extent, fever, which happened mostly after the booster shot. While uncomfortable, those side effects are positive signs that the patient's immune system is launching an immune reaction to the vaccine.

Gloved hands giving an injection into a child's shoulder

Image source: Getty Images.

Like Moderna's (NASDAQ:MRNA) mRNA-1273 and BioNTech's (NASDAQ:BNTX) BNT162b2, CVnCoV is a messenger RNA (mRNA) vaccine that causes the patient's cells to make one of the proteins on the outside of the coronavirus. The patient's immune system should then recognize the protein as foreign and mount an immune response. CureVac, like Moderna and BioNTech, hasn't yet developed an approved and commercialized product using its mRNA technology.

CureVac is in the process of completing a phase 2a clinical trial of CvnCoV in Peru and Panama, and plans to start a pivotal phase 2b/3 study before the end of the year. Shares of the biotech were up as much as 4.5 % Monday morning, but slipped into negative territory during afternoon trading.

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