The end not in sight yet for COVID-19

12 Mar 2020 bởiElvira Manzano
The end not in sight yet for COVID-19

The world is on a race to stem the outbreak of COVID-19*, currently one of man’s greatest nightmares. The end is not in sight yet, the WHO** has predicted.

Cases swell as the virus spreads afield, travelling as far as Estonia and Brazil, and hitting South Korea and Italy outside China the hardest. Easily, nations are beset with fears of a global pandemic. If transmissibility studies in China were to be taken with sobriety, each infected individual generally transmits the virus to two to three other individuals.  Cases could reach a pandemic level of 4 million, according to experts. Without a cure and a vaccine yet, COVID-19 could wreak havoc and carnage on a global scale.

The true number of infections worldwide is hard to estimate. The outbreak starts to gather speed in the US, Europe, and the Middle East. At press time, COVID-19 had killed 4,028 people and infected over 114,545. Singapore had the highest number of cases in Southeast Asia as of March 10,  though recoveries outpaced infection rates, and there were no reported virus-related deaths. Strangely absent from the list are Laos and Bhutan, which border China.

Virus – and rumours – spread like wildfire

COVID-19 has now been detected in over 115 countries. Gary Kobinger, director of the Infectious Disease Research Center at Laval University in Quebec City, Quebec, Canada, said outbreaks have popped up in countries far from China because people with mild infections were not detected and travelled to other places. “If they hadn’t travelled, the virus would not be spreading because we would know where those cases are. The deadly pathogen would be contained and that would be the end of it,” he said. “In the absence of good serology data, it is also completely speculative to say that there are no undetected cases.”

The US Centers for Disease Control and Prevention (CDC) urged the public to know the facts about COVID-19 and help avert the spread of rumours. The virus, the CDC emphasized, can make anyone sick regardless of race or ethnicity. It’s not exclusive to Chinese, to colour, or descent.

How worried should we be?

 “Unlike other epidemic diseases that we’ve seen like Ebola, COVID-19 can be spread through the air, so when people cough and sneeze, and droplets come out and someone inhales them, they can become infected. That means you don’t have to have direct physical contact with someone to become infected. We also think one can even be infectious during the incubation period of the virus,” said Dr Nathalie MacDermott, clinical lecturer in infectious diseases, King’s College London, London, UK. “You’ve been infected but have not shown any symptoms yet. You don’t know you are unwell but could spread the disease to other people, and that makes it harder to contain because you’re asking people who don’t necessarily know they had contact with someone sick to maybe isolate themselves at home to protect others.”

There is also strong evidence that the disease can be transmitted by people who are just mildly ill or even presymptomatic. [N Engl J Med 2020;doi:10.1056/NEJMc2001899] In a detailed analysis of the first 1,099 cases reported in China, fever was not always present on admission and many did not have abnormal radiologic findings. [N Engl J Med 2020;doi:10.1056/NEJMoa2002032]

Older people, and those with underlying health conditions appear to be more vulnerable, so are healthcare workers  caring for the sick. COVID-19 typically causes flu-like symptoms (fever and cough) and shortness of breath. Safety measures by health authorities include washing of hands frequently and staying at home when unwell to keep self and others safe. Reporting symptoms and following quarantine instructions are also crucial in protecting the most vulnerable.

To mask or not?

Transmission routes between people appear to be through close physical contact and tiny droplets in the air. Yet masks are far from fool proof – wearing them does not guarantee one would be COVID-19-free. This is because aerosols can still penetrate the masks and viruses can transmit through the eyes.

However, masks are effective at capturing droplets, which is the main transmission route of COVID-19. Studies have estimated a roughly fivefold protection with masks compared with no barrier at all. A mask cuts the chance of the disease being passed on to an individual should he or she come in close contact with an infected person. But for someone who is just strolling in the park or walking in an empty street, wearing a mask does not make any difference.

MacDermott said masks are beneficial at reducing the spread of aerosols from someone who is unwell and who is coughing and sneezing. But whether a face mask protects a person who is well from being exposed to a virus is another matter. “There is not any good evidence to support that … and people have different opinions.”  

Vaccine in the offing?

The trials required before a commercial vaccine becomes available can be a daunting task. One year is deemed expeditious for a vaccine to be rolled out. And if it were available today, who would get access to it – the people most at risk, or those with deeper pockets?

Aside from vaccines, cheaper, portable tests are the need of the hour. Though most tests are  done by public health laboratories, many companies have developed tests and are moving apace to get those validated for clinical use. A crash programme to develop a vaccine against COVID-19 infection is also underway under the auspices of the Oslo-based Coalition for Epidemic Preparedness Innovations.

No specific antiviral, at least not yet

Currently, there is no specific therapeutic approved for COVID-19. However, some antiviral medicines may alleviate the symptoms. There are reports that some doctors in China and Thailand are giving patients HIV drugs as the global search for a cure continues.

Two phase III studies are underway to test the antiviral drug remdesivir in adults with COVID-19. The trials will enrol approximately 1,000 patients from across countries. A passenger brought back to the US after testing positive for the disease aboard the Diamond Princess cruise ship, and was quarantined, volunteered to take part in the study.

With the rapid upswing in cases, the world needs to plan as if it is facing a pandemic. It is too early to assume when the virus can be eradicated, according to the WHO. As in previous pandemics, Waves 2 and 3 arising after the initial wave recedes are “distinct possibilities.” If an effective vaccine is brought to the fore before COVID-19 picks up steam again, an even more deadly global pandemic will have been aborted.

 

*COVID-19: coronavirus disease 2019