Covid boosters in the fall? As calls grow for third shots, here's what you need to know - CNBC

and U.K., have already signaled that they could roll out Covid-19 booster shots within a year.

Now, pressure is building on governments to mobilize booster shot programs — no easy task given the ongoing uncertainties surrounding the pandemic, vaccines and variants.

First of all, there are question marks over whether we actually need a third dose of any Covid-19 vaccine given that we don't know how long immunity currently lasts.

Booster shots could potentially be rolled out before countries have even completed their initial vaccination programs.

On Monday, the BBC cited a senior government source as saying plans for a Covid-19 booster jab program will be published "in due course" and that "extensive" research was being conducted into the effect of different vaccine combinations.

This is particularly important given that they are under pressure not just from delivering the current vaccination programs, but also tending to the health needs of those patients whose procedures and treatments were delayed as a result of the coronavirus pandemic.

"We do need to know, first of all, whether a booster vaccination program is needed ...

We need to know where they will be given them [the booster shots] and by whom," he said Monday.

"Our GPs and nurses are extremely busy, so is it possible that a booster campaign can be given by non-clinical trained vaccination staff?," he asked, arguing in favor of giving a booster alongside the winter flu vaccination.

On the same radio show, Anthony Harnden, deputy chairman of the Joint Committee on Vaccination and Immunisation (which advises the U.K. government on its vaccination policy) cautioned that who is targeted by any booster campaign should be carefully considered.

There is a moral argument over whether booster vaccination programs are the right thing to do when many less developed countries are lagging in their vaccination programs.

Calls for booster shots come amid rising concerns over the spread of the more transmissible variant delta variant, which WHO's Swaminathan noted Friday was well on its way to becoming the dominant strain globally.