The world has changed beyond all recognition.
In a few short months, everything that we took for granted - visiting loved ones, nipping to the shops for a few essentials, even going to school - have all been replaced by a regime of social distancing and strict hand hygiene.
With the new way of life has come a whole new vocabulary, words that were once alien to most have now become common, everyday phrases. Coronavirus, epidemiologist and shielding - they're all words that are now part of the wider public consciousness.
One of the phrases being used increasingly as we move beyond the first deadly surge of Covid-19 is the reproduction number, known more simply as the R value.
At its most basic, the R number is a way of rating a disease's ability to spread.
Essentially, it is the average number of people that one infected person will pass the virus on to.
For example, if a virus has an R value of three, it means that every sick person will pass the disease on to three other people if no containment measures are introduced.
It follows, therefore, that the lower the R number, the smaller the number of people who are being infected.
Now we are a few months into the pandemic, fatigue is setting in - the economy is crumbling, children are falling behind in their education, non-Covid patients are coming to harm, so attentions are turning to trying to regain some kind of normal.
But the virus hasn't changed - it is still as virulent, there is no vaccine and no cure, so it is essential that any relaxation of social distancing measures does not result in an increase in the number of cases of Covid-19.
To this end, the R number is being relied upon by scientists and policy makers as a key indicator on how Covid-19 is spreading throughout the community.
Given its significance, it is little wonder that the R rate is being referred to so frequently by our politicians as they explain what lockdown measures are being lifted and when.
But how much does the general public really know about the R number?
The Northern Ireland Assembly Research and Information Service has urged caution against an over reliance on the R rate as we move beyond the first surge of Covid-19.
"While R provides a useful indication of the potential of the disease, helps to inform policy in the fight against the disease and gives some indication of what progress has been made in that fight, it is necessary to be aware of its limitations and weaknesses," the document warns.
"The information going into the equations used to estimate R is far from perfect."
The reasons for this are plenty, it argues. First and foremost, we don't know how many people are infected, while we also have no idea how many people are immune to the virus.
"Without reliable information on the number of people who have been infected, it is not possible to estimate the number in the population who may have acquired immunity and therefore the number who may still be susceptible," explains the document.
Of course, the number of diagnostic tests is being ramped up which will give a clearer picture of the infection rate.
This in itself will pose additional problems because, as more tests are carried out, more people will be diagnosed.
However, it is impossible to say how much of any change over time is due to the rate of the spread of the virus.
The briefing document also refers to the uncertainty over the incubation period for the virus, with estimates ranging anywhere between two and 14 days.
The duration of infectiousness also differs greatly, while the impact of the disease varies from person to person. Some people escape without any symptoms at all and they may be less infectious, but they are impossible to identify without testing.
The time lag in the reporting and registering of deaths and a change in death rates are also factors in muddying the waters when it comes to the R number, according to the briefing document.
Interestingly, the paper refers to the fact that death rates can change as more vulnerable people die, leaving the disease with less vulnerable people to kill, while at the same time they can also change due to hospitals getting better at treating the disease.
It also points out the holes in data currently being recorded around hospital admissions.
While they provide a useful indication of trends in the spread of the disease, they do not include people being treated in care homes and those who may be seriously ill or dying at home.
The time lag between infection and the availability of data to input into models to determine the R value means they are historical.
The briefing document continues: "Given the uncertainty that arises from all of this, R and many of the other numbers associated with Covid-19 must be interpreted with considerable caution.
"The many assumptions and estimates built into the models, the quality of the data and the time lag in the data could potentially lead to wrong decisions being taken at the wrong time, if too much reliance is placed on a single number."
Of course, as the briefing paper notes, the scientists working out the R rate are sure to be more than aware of all the issues relating to their calculations.
The public less more so and it warns of the dangers of our politicians relying too heavily upon the R number as a catch all explanation for their decisions, without explaining the caveats.
At the end of the day, moving beyond the lockdown is a fine balancing act - lift measures too soon and lives will be lost, but it is equally as dangerous to keep the status quo in place indefinitely.