Currently the Duke and Duchess of Sussex are living in California with their son Archie. The couple stepped down from front line royal duties at the end of March.
Harry celebrated turning 36 on Tuesday.
According to Ms Barger, deputy editor of Royal Central, he is likely to have spent the day at home with Meghan and Archie.
She added other senior royals will likely “miss not being able to celebrate him” but they will still be able to see each other via video calls.
However, speaking to the Daily Star online, Ms Barger pointed out that even if the Duke and Duchess had remained in the UK they “couldn’t have spent his birthday with many family members”.
Currently the “rule of six” means it’s illegal for any more than six people to socialise together in England, Scotland and Wales.
In England this even applied to under 12s, like Archie, whilst in Scotland and Wales they are exempt.
This means Harry and Meghan would be able to have a maximum of three guests to their Frogmore Cottage home near Windsor.
Ms Barger said: “I’m sure The Queen will call him, as will his father and brother.
“I’m sure they will miss not being able to celebrate with him.
“But with the new restrictions in the UK of only six people, he couldn’t have spent his birthday with many family members.”
Harry and Meghan caused a global sensation back in January when the couple announced they would be stepping down as frontline royals.
Instead the couple said they aimed to become “financially independent” whilst splitting their time between North America and the UK.
After a brief stay in Canada the Duke and Duchess moved to California shortly before the state went into coronavirus lockdown.
They recently moved into a new £11.2million home to the north of Los Angeles.
The property reportedly includes a swimming pool, tennis court and guest house.
Last week streaming giant Netflix announced a landmark deal with Meghan and Harry.
The couple will produce documentaries, films and children’s programmes for the service.
In March Prince Charles caught coronavirus but recovered after only suffering mild symptoms.
To keep her safe the Queen spent the first lockdown in Windsor Castle.
From here she delivered an emotional address to the nation commenting: “This time we join with all nations across the globe in a common endeavour, using the great advances of science and our instinctive compassion to heal.
“We will succeed – and that success will belong to every one of us.
“We should take comfort that while we may have more still to endure, better days will return: we will be with our friends again; we will be with our families again; we will meet again.”