Can we trust new coranavirus vaccines?

While BioNTech and Pfizer, as well as Moderna, are leading the race to develop a COVID-19 vaccine, other pharma companies — such as Sanofi, Sinovac and Johnson & Johnson — are expected to soon present candidates of their own.

According to the World Health Organization, 47 vaccines candidates are currently in clinical trials, of which 10 are in phase 3 efficacy trials. Russia has already registered two vaccines, one of which — Sputnik V — became available for public use in August. Experts, however, warn that this vaccine has been insufficiently tested.

Open questions

Many questions, however, remain unanswered. It is unclear, for instance, how effective these vaccines are, and how they affect individuals of different ages and those with pre-existing medical conditions. Little is known about whether the vaccines lead to long-term immunity, or if they can prevent severe, or indeed asymptomatic COVID-19 infections.

It is also not known how much the vaccines will cost, who will have access to them and in what quantity and at what time, and how they will be distributed around the globe.

Are the vaccines safe?

Independent monitoring groups registered no serious safety concerns with the vaccines being developed by BioNTech/Pfizer and Moderna. This does not, however, rule out the possibility of serious side effects occurring during large-scale testing, or when vaccines are given to persons with rare pre-existing health issues.

Intramuscular injections also bear to the risk of causing local reactions. Moreover, immune responses that entail the production of B cells and supportive T cells can lead to fever, chills, muscle aches or headaches.

In addition, both vaccines — BioNTech/Pfizer's BNT162b2 and Moderna's mRNA-1273 —  belong to a new family of vaccines that so far has not been approved for medical use. They contain nucleoside-modified messenger RNA which functions as a blueprint for the virus spike protein. Once administered, the vaccine stimulates the human immune system to produce antibodies against this protein and thus the virus.