Queen Elizabeth and Prince Philip's health are being carefully protected against the coronavirus pandemic. A new memo details what measures are being done to ensure the safety of Her Majesty and her husband, the Duke of Edinburgh, who are both vulnerable to COVID-19, the disease caused by the virus.

According to Daily Mail, the memo was prepared by Master of Household Tony Johnstone-Burt for the 22 staff serving Queen Elizabeth and Prince Philip in Windsor. Among the demands from the royal household include disallowing them from returning home to their families while the lockdown is still in effect. 

Essentially, this means that the royal staff members have not seen their family for over six weeks since the government of U.K. has issued the stay-at-home orders. Johnstone-Burt called this protocol the "HSM Bubble" in reference to Prince Philip's stint in the Navy. 

"It struck me that our predicament is not dissimilar to my former life in the Royal Navy on a long overseas deployment," said Johnstone-Burt, who was also formerly a Navy, in the memo. "The challenges that we are facing whether self-isolating alone at home, or with our close household and families, have parallels with being at sea away from home for many months." 

Johnstone-Burt said that protecting Queen Elizabeth and Prince Philip is the most important duty right now for those in Windsor Castle. Hence, the strict orders to remain in the premises so that no one going outside would catch the virus and potentially bring it to the royal household. 

The Queen and Prince Philip are also making sacrifices as they have not seen any family members since going in isolation in the middle of March. They have, however, been touching base via video conferencing and other digital platforms. 

In early April, the Queen addressed the nation to assure the public in a rare speech of overcoming this pandemic.

"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," the Queen said. 

Earlier, it was speculated that Queen Elizabeth needed only eight of her most reliable staff members to serve her is insolation at Windsor Castle. These include trusted aides like Paul Whybrew and Angela Kelly, along with the chef, a footman and a few house helpers. 

The royals will remain in isolation in Windsor potentially until the end of May. The U.K. has extended the lockdown until the middle of the month but there could be more days in isolation as the country has yet to flatten the curve of infection.