Even without a Covid-19 vaccine, there's reason for hope - CNN

But in the case of Covid-19, according to one study, not everybody infected by the virus makes the neutralizing antibodies that are necessary to clear the virus and fewer still make them in high numbers.

What we know from nearly 60 years of observing coronaviruses is that even if a body's immune system can clear the virus, the pathogen can likely reenter the system and cause illness again.

The first are antivirals -- drugs that act on the virus itself and prevent it from replicating.

With this drug -- and with the other set of monoclonal antibodies already researched -- there is a question of whether they are going to be effective against a virus like SARS-CoV-2 that lives primarily in the nose and the lungs instead of in the blood.

That said, monoclonal antibodies have worked against the respiratory syncytial virus, which has many similarities to SARS-CoV-2.

Much like the vaccines that have showed early promise, these drugs too will need more testing before their safety and efficacy can be proven.

For antivirals and monoclonal antibodies, you know whether the virus works within a matter of days -- either the viral load in the patient goes up or it goes down -- and with very few individuals.