It was Christmas time and the whole family was gathered together, but Maria Van Kerkhove was distracted: she had just received an email alert about mysterious pneumonia cases in China.

In the nine and a half months since then, that first cluster of cases has ballooned into a devastating pandemic, and the 43-year-old American epidemiologist has been thrust to the forefront of the World Health Organisation's battle against Covid-19.

Read: Coronavirus may never go away, says WHO

“I am immensely proud to be part of this team,” she told AFP in an exclusive interview this week, pointing to the huge amounts of knowledge amassed about the disease in a few short months.

She acknowledged though that “this is far from over”.

The new coronavirus has killed nearly 1.1 million people worldwide since Van Kerkhove and other disease experts were first alerted to the mystery virus late last December.

The specialist in high-threat pathogens was at her sister's home in North Carolina over the holidays with her husband and their two young sons when she heard of the outbreak of pneumonia cases of unknown origin in Wuhan.

“That immediately raised alarm bells,” she said, recalling taking emergency calls at 3am "sitting on my sister's living room floor while the family was asleep".

“It has been non-stop since then.”

Also read: Three major scientific controversies about coronavirus

Media storm

After spending years of behind-the-scenes research of dangerous diseases like Ebola, avian influenza and MERS, Van Kerkhove participated in her first-ever press conference on January 14, explaining what was known about the new mystery virus to journalists in Geneva.

She thought it would be a one-time thing.

Instead, she has for months featured at multiple press conferences a week alongside WHO chief Tedros Adhanom Ghebreyesus and emergencies' director Michael Ryan.

She acknowledged the situation had been a bit surreal.

“I almost feel like it is happening to someone else,” she said.

Van Kerkhove, who is WHO's technical lead on the pandemic, speaks calmly and deliberately, often gesticulating for emphasis as she conveys complex scientific findings and WHO's core messages on how to halt the virus.

She said she feels a deep sense of responsibility to accurately and honestly convey what WHO knows and doesn't yet know about the virus, and "that we are here to help".

'Misrepresented'

But for the accomplished researcher, with degrees from Cornell, Stanford and the London School of Hygiene and Tropical Medicine, the communication task has sometimes been challenging.

“We don't always get it perfect,” she said, recalling with frustration the firestorm that erupted after her comment during a June press conference was “willfully taken out of context”.

She had said people who never develop symptoms of Covid-19 appear to only rarely transmit the virus, but her comment was interpreted to mean that pre-symptomatic people who later develop symptoms are not contagious.

People said “there you go. It's not important. Open up your societies,” Van Kerkhove lamented.

“Those are the kinds of things that really bother me because I know what we say matters,” she said.

The episode “weighs quite heavily on me”, she acknowledged, adding that the purple shirt seen in the clip that continues to circulate despite WHO's efforts to set the record straight is one “I will never wear again".

As one of the most visible faces of WHO's pandemic response, Van Kerkhove has also had to deal with personal attacks on social media.

She said she tried not to look at the negative and sometimes violent comments, preferring to focus on messages of support, including from girls proud to see a woman scientist in such a prominent position.

'Unbelievably supportive'

Van Kerkhove acknowledged the work had been hard. She barely made it home for the first six months and has yet to take a full day off.

“It just feels like one continuous long day”, she said, adding that her husband had been “unbelievably supportive”.

After she took part in a mission to China in February, she stayed away from her family for weeks for fear she might expose them to the virus.

Her eldest son, who is nearly 10, had worried she might not return from China, and her youngest, nearly two, did not understand her efforts to quarantine in her bedroom.

“When I would come home, the baby would come and run after me. He thought it was a game,” she said. “I would run into our room and cry.”

Since then, she said, her family like everyone else's was trying to find their way in “this new normal”.

"That is something we are all working through."