With much of the world either in lockdown or contemplating an imminent return to it, it can be forgiven its bated breath as it awaits news updates on any little progress that may have been made towards developing a vaccine for Covid-19. A process which typically takes many years would appear to have been pared down to a scramble over a matter of months, and some 240 potential vaccines are presently under development in various places across the globe, including forty in clinical trials and nine in the final stages of testing.

For governments and their scientific advisors all bearing a tired aura of folks who have run out of ideas, a vaccine is undoubtedly the holy grail in the fight against Covid. New restrictions imposed are invariably prefaced with the words "until we have a vaccine". Of course new vaccines do not always work, and so it is necessary to sound the obligatory note of caution. But assuming at least one does, what, realistically, is the best we can expect from it?

Are we expecting too much of a vaccine?

Assumptions are frequently made that a vaccine is the panacea which will finally consign the ubiquitous SARS-CoV-2 to history. But are we pcr test chicago expecting too much of it, at least in the early stages?

In the field of medicine there is a concept called "sterilising immunity", wherein a vaccinated individual can expect total protection from a virus. But coronaviruses are rarely that co-operative. Instead it is much more likely that inoculation will provide efficacy at, say, 50%, meaning the vaccine will be a huge step forward but it won't make the virus disappear, at least not overnight.

Possibly the most advanced of the Covid-19 vaccine projects presently under way is that being developed by Oxford University and AstraZeneca. Experiments undertaken in macaques as part of this project showed that the vaccine protected the primates from developing pneumonia, but quantities of virus remained in the upper airways.