Even as the number of cases rises dramatically in Europe and North America, the coronavirus has peaked in several Asian countries, and the first research on the longer term effects of the virus is emerging.

How long does it live in your body?

A study by The Lancet medical journal gives a sobering answer. It reports that coronavirus patients can keep the pathogen in their respiratory tract for as long as 37 days, meaning that they could remain infectious for many weeks.

Given that the current quarantine period is recommended as 14 days, patients might remain contagious long after their symptoms vanish, unwittingly spreading the virus further.

Can you get it again?

There are isolated reports of people apparently getting reinfected with coronavirus. Data from health officials in China’s Guangdong province reported that 14 per cent of people that recovered then tested positive again.

In late February, Reuters reported about a woman in Osaka, Japan that also tested positive having recovered from a previous infection. A similar case was reported in South Korea.

However, there might be other explanations rather than reinfection. There is the possibility of it remaining dormant after an initial bout of sickness with minimal symptoms, before it attacks the lungs. Or there is always human error such as inaccurate testing or patients being discharged prematurely.

Typically, when a viral infection is defeated by the body’s immune system, it knows how to defeat it again — they are immune. An exception would be if the patient is in some way immunodeficient.

Anthony Fauci, director of the National Institute of Allergy and Infectious Disease, noted in a hearing before the House Oversight and Reform Committee on Thursday: “We haven’t formally proved it, but it is strongly likely that that’s the case. Because if this acts like any other virus, once you recover, you won’t get reinfected.”

What are the lasting effects if you recover?

The Hong Kong Hospital Authority studied the first wave of patients to recover from confirmed cases of the virus. The city had 131 cases and three deaths, and a total of 74 people have been discharged.

Dr Owen Tsang Tak-yin, medical director of the authority’s Infectious Disease Centre at Princess Margaret Hospital in Kwai Chung, said doctors had already seen approximately a dozen discharged patients in follow-up appointments. Two to three were unable to do things as they had in the past, The South China Morning Post reports.

“They gasp if they walk a bit more quickly,” Dr Tsang said at a media briefing on Thursday. “Some patients might have around a drop of 20 to 30 per cent in lung function [after recovery].”

The patients will now undergo tests to determine how much lung function they still had, and physiotherapy and cardiovascular exercise would also be encouraged to strengthen their lungs.

Scans suggest there is organ damage to the lungs, but it was so far uncertain whether this could lead to complications later in life such as pulmonary fibrosis.