COVID-19: your questions, answered

With so much conflicting information about the coronavirus pandemic swirling around the internet, we invited the Forum's Instagram followers to put their questions about the crisis to a panel of medical experts from around the world.

You can have it and display no symptoms depending on your age, how strong your immune system is and how recently you have been exposed. Because it is extremely contagious, the virus can be transmitted easily - even by individuals without symptoms - which is why it is important to practice preventative measures even if you feel fine.

- Dr David Walcott, World Economic Forum Global Shaper and founder of NovaMed

Yes - because the time from when you catch the COVID-19 virus to when you begin to show symptoms is five days on average. However, this time period, also called the incubation period, has been known to vary between 1-14 days - and people can be infectious during this period. Additionally, if you have no symptoms but are a carrier of the virus, you could risk passing it on to others, for whom it could be fatal. So, follow the advice of your local and national governments and practice social distancing.

- Dr Kate Tulenko, CEO of Corvus Health

Currently it is unknown how long the immunity of COVID-19 patients can last. However, the virus could potentially mutate in such a way as to cause patients to become susceptible again.

There are reports of recovered COVID-19 patients being tested positive again in China, South Korea and Japan. However, solid scientific evidence is needed to address questions like: How accurate were the test results? Was the recovered patient reinfected with the virus, or did they have an infection that simply lasted a long time? Are there variations in immune response among different people? How many different versions of COVID-19 may be spreading around? These questions could help us understand the immune response of the virus.

- Dr Xifeng Wu, Dean and Professor of School of Public Health, Vice President of The Second Affiliated Hospital, Director of National Institute for Data Science in Health and Medicine, Zhejiang University, Hangzhou, China

- Dr Zhi Chen, Professor of State Key Laboratory for Diagnosis and Treatment of Infectious Diseases, National Clinical Research Center for Infectious Diseases, The First Affiliated Hospital, Zhejiang University School of Medicine, China

This depends on the surface material and the amount of virus present. A recent study investigated the persistence of coronavirus on stainless steel, plastic, cardboard and copper. The authors used an initial virus concentration similar to that found in the respiratory tract of infected people. The virus remained detectable for between 10 hours and three days, with the shortest persistence on copper and the longest on plastic. Another study that looked at the related virus SARS-CoV - the virus responsible for the SARS outbreak in 2003 - found it was detectable for up to nine days. However, just because a virus is detectable does not mean it poses a health risk.

So an interesting related question is: How long should we worry about becoming sick from touching a contaminated surface? The answer to this is probably shorter than three to nine days. One reason is that the virus concentration on surfaces declines over time as it dries out, so the longer the time since contamination, the lower the risk. A second reason is that only a portion of the total virus will transfer from the surface to your hand to your mouth or nose. Nevertheless, risks from surface contamination in highly trafficked areas provide additional motivation to wash your hands frequently with soap and water and disinfect surfaces regularly.

- Dr Tim Julian, Group Leader of Pathogens and Human Health, Department Environmental Microbiology, Eawag - Swiss Federal Institute of Aquatic Science and Technology

The diversion of healthcare resources to manage the COVID-19 crisis has significantly affected the ability of many health systems to maintain standards of care for patients with other medical conditions. Hospitals in the worst-affected countries are struggling to keep pace with the number of admissions from the coronavirus alone, and have almost zero capacity to cope with other conditions. Even in countries that are not as badly affected, many hospitals have now deferred elective surgeries, redirected any upper respiratory tract infection or pneumonia cases to isolation wards, and cancelled or postponed non-critical outpatient clinic visits.

This also means that people are deferring their health checks, including screening tests to pick up cancer incidence. The latter in particular means there will be patients who would otherwise have been identified through routine screening as being in need of urgent medical attention, and these are now missed or delayed – which means the window of opportunity for seeking early or effective treatment may be closed, resulting in morbidity or mortality that could have been avoided. The situation may be compounded when the supply chains for essential medicines are disrupted, a reality that is starting to happen in several countries which are key producers of medical supplies.

- Professor Yik-Ying TEO, Dean, Saw Swee Hock School of Public Health, National University of Singapore

Over the past 30 years, the number of annual epidemics has nearly tripled. In the past 15 years alone, outbreaks of Zika, MERS-CoV, SARS, cholera, tuberculosis, HIV/AIDS, influenza and Ebola have killed hundreds of thousands of people.

We know why this is happening. We live in a world where humans are increasingly connected — not only to each other but also to animals, which are responsible for about three-quarters of new infectious diseases.

What’s more, human beings are moving around the planet faster than at any other time in history, giving pathogens endless opportunities to find new hosts, cross borders and evolve into stronger strains than we’ve seen in the past.

Climate change is also fuelling the spread of disease, as warmer temperatures disrupt our ecological balance and expand the habitats of mosquitoes and other disease-carrying species. Meanwhile, antimicrobial resistance is undermining some of the gains we have made in controlling outbreaks, as infections become more difficult — and even impossible — to kill.

The next pandemic is only a matter of time. And as has become painfully obvious over these past few weeks, we remain dangerously underprepared.

- Michelle A. Williams, Dean of the Harvard T.H. Chan School of Public Health, US

There are currently no specific vaccines for COVID-19 that are immediately available; however, there are many potential vaccines currently being researched and developed.

For a vaccine to be developed, we have to identify and understand the structure and behaviour of the virus, then conduct extensive laboratory and human testing. Fortunately, we have been able to identify the virus and sequence its DNA quickly, and we now understand that it is very similar to two previous viruses that we know a lot about: SARS and MERS. However, a certain amount of time is required to understand how safe and effective the vaccines are in preventing disease. We have to ensure that any vaccines are not harmful and offer effective protection against the coronavirus. Based on the timeline required for this, there is unlikely to be a vaccine offered to the general public within the next 12 months.

- Dr David Walcott

There is currently no approved vaccine for COVID-19. Vaccines usually take at least a year from first human trials to regulatory approval - however, due to the urgency of the need for this vaccine, it may be made available to health workers and high-risk individuals in six to nine months.

- Dr Kate Tulenko