LONDON, April 6 (Xinhua) -- People still need to know a lot about the natural history of COVID-19, including what the disease looks like in various people and how transmissible it is from one person to another, said David Heymann, professor of Infectious Disease Epidemiology at London School of Hygiene & Tropical Medicine.

"We know how it (the virus) is transmitted. We don't understand its transmissibility from person to person, how easy it transmits, and when at the stage of infection it transmits," Heymann, head of the Centre on Global Health Security at Chatham House, told Xinhua in a recent phone interview.

Referring to the current international collective efforts for the research on COVID-19, he believes "what's been going on presently is what's the most important research."

"There are two priorities, drugs to treat the disease and drugs for prophylaxis and vaccines," Heymann explained.

Meanwhile, he also emphasized the importance of studies about antibody preparations, "to see if they have any place or role to play, to prevent in prophylaxis or in treatment".

One pillar of the British government's latest action plan is introducing antibody blood tests and surveillance to find out what proportion of the population already have the virus by using an antibody test.

Heymann agrees it is very important to understand who has been infected in the past and to better understand the genealogy of infection. However, the former World Health Organization (WHO)'s assistant director-general for health security and environment, stressed that those tests must be validated as highly specific and sensitive. His earlier experiences include chief of research activities in the WHO global programme on AIDS.

To respond to COVID-19, many countries are using a combination of containment and mitigation activities with the intention of delaying major surges of patients. Among those activities, social distancing is most widely introduced in countries including Britain.

"Social distancing is one way," said Heymann, "In addition to that, protect others by using a mask and if you're sick, isolate yourself and stay away from all your family members, as you can."

"Another way is making sure that there is infection prevention and control measures in hospitals," he added, noting that hospitals are one of the main places where the virus spreads.

At present, stages of the epidemic and measures being taken to stop the spreading of the virus vary from country to country across the world. Asked about the next steps that countries like China should take, he told Xinhua that it should be done according to the risk assessment.

"I believe what China is doing is evaluating which measures are most effective," he said.

"China has a very excellent history of epidemiology risk assessment. And they know how to do measures that are appropriate for the country," he added.