The SNP's Westminster leader took to the floor at Prime Minister's Questions on Wednesday but appeared to have almost totally lost his voice as he struggled to get his words out.
It prompted viewers to speculate what in fact is going on as they questioned why Mr Blackford was without a mask.
@andysstuff tweeted: “Why is Ian Blackford maskless with that cold or worse?"
While @Deew04 noted: "Ian Blackford sounds like he has a nasty cold... #PMQs"
@Smicht noted: "Jesus, Ian Blackford shouldn't be at work with a throat like that."
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But Guido Fawkes reporter Christian Calgie joked: "Joyous! Ian Blackford's lost his voice!"
The backlash comes amid rising concern amongst ministers as Covid cases in the UK have soared in the past week.
It comes as Monday saw the highest daily Covid death toll since March as fears rise over what is in store this winter.
223 deaths were recorded within 28-days of a positive test on Monday
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While on Tuesday, a further 43,738 coronavirus cases were reported, down slightly on Monday’s figure.
But daily hospitalisations have continued to rise, reaching 921 Britons in hospital - that figure sees hospitalisations up 10% on the week before.
Covid rates are soaring among largely unvaccinated secondary school children and infecting older and more vulnerable age groups.
Those impacted are aged 50 and over and leading to the rising death and hospitalisation figures.
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It comes as Health Secretary Sajid Javid will lead a televised coronavirus press conference at 5pm today, amid fears of a winter surge of the virus.