The first clinical data on vaccines developed by pharma giants Pfizer and BioNTech were disclosed Wednesday in a paper released on MedRXiv . Early results have shown that the treatments have spurred immune responses in healthy patients. However, higher doses have been shown to cause fever and other side effects.
From the CNBC article:
The Pfizer study randomly assigned 45 patients to get one of three doses of the vaccine or placebo. Twelve receive a 10 microgram dose, 12 a 30 μg dose, 12 a 100 μg dose, and nine a placebo. The 100 μg dose caused fevers in half of patients; a second dose was not given at that level.
Following a second injection three weeks later of the other doses, 8.3% of the participants in the 10 μg group and 75% of those in the 30 μg group developed fevers. More than 50% of the patients who received one of those doses reported some kind of adverse event, including fever and sleep disturbances. None of these side effects was deemed serious, meaning they did not result in hospitalization or disability and were not life-threatening.
The vaccine generated antibodies against SARS-CoV-2, the virus that causes Covid-19, and some of these antibodies were neutralizing, meaning that they appear to prevent the virus from functioning. Levels of neutralizing antibodies were 1.8- to 2.8-times the level of that in the recovered patients.
The results were published in a preprint server, meaning it has not yet been peer-reviewed or published in a journal. The paper DID say that more diversity would be required for future tests. Fourteen Covid-19 vaccines are also in development.