I believe that, in different conditions, we should reasonably ask that more people be tested over a longer period of time.

But Covid is wracking absolute havoc on people's health, on the economy, and on everyone's lives. Personally, I plan to take the Pfizer or Moderna vaccine as soon as it is available. There are associated risks -- but in my estimation, they are not as bad as the risks of Covid infection or the downsides of continued social isolation.

I'm happy about the sample size, but are long term longitudinal studies typically required?

The long-term effects of covid itself are a far bigger concern to public health authorities.