Foreign Secretary Mr Raab, who is deputising for the PM as he recovers from Covid-19, and Sir Keir will be in the House of Commons chamber among up to 50 MPs permitted to attend.
Some 120 more can take part remotely through the Zoom video-conferencing platform in the first PMQs since Parliament rose early a month ago because of the crisis.
It comes as the Government faces allegations of being slow to act in imposing a lockdown on the UK as other countries took the drastic measure.
Sir Ed Davey, the Liberal Democrat’s acting co-leader, has called for an independent inquiry to be held into its “shocking failures” and “slow response” to the crisis.
As the death toll exceeded 17,000, the Government also came under fire with its commitment to reach 100,000 tests per day by the end of the month appearing an ambitious hope.
Ahead of the first ever virtual PMQs later on Wednesday, Health Secretary Matt Hancock said the Government is “throwing everything” at developing a coronavirus vaccine.
He announced that human trials led by the University of Oxford will begin on Thursday.
Mr Hancock said it was clear that the “best way to defeat coronavirus is through a vaccine” and that “rapid progress” was being made.
Oxford, where the team is being led by Professor Sarah Gilbert, has said it hopes to have at least a million doses of its vaccine ready in September, while Imperial hopes to start clinical trials in June.
On the issue of Covid-19 testing, Mr Hancock said it was “terrific” that capacity was increasing across the UK, saying it was further ahead than the planned trajectory.
This is despite the fact less than half of the available coronavirus testing capacity has been used, with just 19,316 tests conducted in the 24 hours to 9am on Monday against capacity for 39,250.
The Government is likely to face further questions about its participation in an EU scheme to secure vital equipment.
This comes after the Foreign Office’s top civil servant, Sir Simon McDonald, made an extraordinary U-turn in withdrawing his own claim that the UK did not take part because of a “political decision”.
Sir Simon wrote to the Commons foreign affairs committee to say his earlier evidence was “incorrect”.
He said the UK had not initially joined the scheme because of a “communication problem”, after Mr Hancock was forced to deny the earlier claim.