“At first we thought that this virus didn’t pass on if you didn’t have symptoms, then there were policy consequences from that assumption.”

That was what Matt Hancock told BBC Radio 4 this morning, on the anniversary of England’s first national lockdown. He’d been asked whether ministers would admit to mistakes they made in their handling of the pandemic. This was “one of the examples I think of”, he said.

His junior minister Helen Whately said yesterday on Times Radio that “our understanding at the beginning was that you would know if somebody was infected or possibly infected because they would have symptoms”.

But it’s not clear what period of the pandemic either minister is referring to.

As early as 28 January 2020 – three days before the first confirmed UK case of coronavirus – the SAGE committee of advisors warned: “There is limited evidence of asymptomatic transmission, but early indications imply some is occurring.”

A study published in the Lancet on 24 February 2020 described its own findings as “suggesting that infected individuals can be infectious before they become symptomatic”, so-called “pre-symptomatic transmission”.

NHS guidance for clinicians from 3 March recommended: “A person that is asymptomatic […] with a Coronavirus travel history or contact with a confirmed coronavirus case” should be “advised to stay indoors” and “avoid contact with other people”. The implication being that even those who do not currently display symptoms could have the virus and infect others.

Throughout March several other sources (including the European and US Centers for Disease Control) acknowledged evidence of pre-symptomatic and asymptomatic transmission.

On 26 March, Professor Yvonne Doyle of Public Health England was asked by MPs on the Health Select Committee whether “people could be spreading the virus to others for up to five days before they show any symptoms”. Professor Doyle replied: “Yes, that is correct.” She added: “we are still learning about that. It ranges over quite a long range, but in the majority of cases that we are analysing, about five days is the period.”

Nevertheless, on 2 April, the UK government issued guidance to care homes in England that said: “Residents may also be admitted to a care home from a home setting. Some of these patients may have COVID-19, whether symptomatic or asymptomatic.”

On the same day, a World Health Organization situation report stated that “some infected persons can be contagious” in the pre-symptomatic phase of the virus and that “transmission from a pre-symptomatic case can occur before symptom onset”.

And a study published by US and Israeli researchers, also on 2 April, said of coronavirus: “it is common to be contagious before symptoms” and “a large fraction of infections occur pre-symptomatically, that is, without the infectious person realizing they have the disease”.

It’s not the first time the two ministers have made questionable comments about when the government became aware of asymptomatic transmission.

Mr Hancock said in July 2020 that symptom-free spread was “not known about” in defence of the care homes policy. And as FactCheck reported recently, Ms Whately made a near-identical claim last month.

When we asked the Department for Health and Social Care about Ms Whately’s earlier claim, a spokesperson told FactCheck on 2 February 2021 that “at the start of the pandemic, the evidence for asymptomatic transmission was still limited.”

In other words, the data wasn’t perfect – this is certainly true, as we reported then – but it was known about. This would seem to contradict the claims from Mr Hancock and Ms Whately this week.

Update: After we published this article, the Department for Health and Social Care told us in a statement: “Covid-19 is a new virus and at the start of the pandemic the evidence around asymptomatic transmission was limited.

“We kept our advice and approach under constant review and acted decisively as more evidence and scientific data emerged. This includes rapidly rolling out extensive community testing to find asymptomatic cases and break the chains of transmission.”

FactCheck verdict

Matt Hancock said today that “at first we thought that this virus didn’t pass on if you didn’t have symptoms”.

However, we know that as early as January 2020 – before the UK had confirmed its first cases of Covid – SAGE warned that there was some evidence of symptom-free transmission.

The data, albeit imperfect, continued to mount up through February and March and was acknowledged by leading health authorities.

Regarding a similar claim from junior health minister Helen Whately last month, the Department for Health and Social Care acknowledged in a statement to FactCheck that there was some evidence for asymptomatic transmission “at the start of the pandemic”. This would seem to contradict what Mr Hancock said today.