CURRENT DATA ON THE 5 LEADING COVID-19 VACCINE CANDIDATES
All the vaccines may require two doses to induce high neutralizing antibodies and T cell responses, which could make it make it more challenging to meet manufacturing projections.
All five vaccines were able to induce neutralizing antibodies in study subjects.
At their highest doses, the vaccine from Moderna produced the most neutralization activity across the five vaccines, though direct comparisons need to be taken with a grain of salt due to the different assays employed to measure the activity.
CanSino Biologics reported the lowest neutralizing antibody titers of the group.
AstraZeneca and the University of Oxford vaccine approached the 160 benchmark at its high dose.
The Pfizer vaccine produced less neutralization activity than delivery of the lowest two-dose regimen (a pair of 1 µg doses) in a Phase I/II study, supporting use of two doses of that vaccine as well.
Sinovac Biotech reported that a two-dose regimen of their vaccine led to 90% neutralizing antibody response rate in a Phase II trial.
All of the vaccines also induced T cell responses in subjects, which could facilitate long-term protective immunity.
The ability to trigger a humoral and cellular immune response is important at this stage because it isn’t yet clear which will correlate with protection against infection.