The country could be well on its way to herd immunity, the point at which enough people are protected against a disease that it cannot spread through the population.

More than a quarter of the population may already have natural immunity after previous infection -- and that number may be much higher than official counts show.

However, some new variants threaten progress, potentially lessening protection offered by vaccines and skirting some degree of natural immunity.

But if you had to put a number on it, what level of population protection is required to reach herd immunity against Covid-19?

We all expect that this virus is not different from other viruses and that we will reach a point that a sufficient number of people are immune so that the virus cannot jump any more.

The number of cases is the threat, and in the declining curve, we see that the number of people it can jump to is dropping.

Can we count those people toward herd immunity?

The number of people known to have reinfection is very low.

But despite all this virus still floating around, people are not getting sick again, and to me that's really encouraging

Lessler: In the short term, over the next six months or so, I would count everybody who's been infected and most people who have been vaccinated as immune.

We know variants are out there, but there are still very few cases of documented reinfection.

What that suggests to me is that variants are not evading immune defense.

In a completely susceptible population, the average person with the original strain would spread the virus to three people, so you need two people to be immune to start decreasing the spread.

But with some variants, the average person may spread the disease to around five people, so you need four people to be immune to cut the spread.

Malaty Rivera: The conversation around variants really needs to be around preventing infection.

The quicker we get to higher levels of protection in our community, the chances for new variants to spread and develop diminishes.

Murray: There isn't a very clear route to herd immunity if those variants spread, and it's a very tricky business trying to predict at what pace they'll spread.

They don't represent a large group of people in this country, and I don't think they'll have tremendous victory when it comes to things like herd immunity.

Mehta: It's really understandable why some people in our communities may have hesitation around the vaccine.

Murray: If we can move from 25% of the population not being vaccinated to 10%, that really boosts herd immunity way up.

Some of this comes down to deciding what is normal, because the fact of the matter is we need to accept the fact that we will be living with this virus forever.