COVID-19: when can we call it safe and go back outside?

The World Health Organization (WHO) declared the pandemic of coronavirus disease 2019 (COVID-19) to be a global health emergency on March 11, 2020. To date, the ongoing outbreak has infected more than 6 million people and killed about 6 percent of them in over 200 countries. Due to the severe situation, many countries have imposed a “stay-at-home” order, which has abated the infected rate, but also brought a record number of economic losses and great inconvenience to the people’s daily life. Governments are endeavoring to get societies out of lockdown and promote economy. Meanwhile, people urgently want to return to work and hang out with friends and families. So when can we call it safe and go back outside? Here are some perspectives. 

When mass nucleic acid test is available

Nucleic acid test has played an important role in containing the spread of COVID-19. If we can take nucleic acid tests to the entire population, screen out and quarantine the carriers of SARS-CoV-2, the others can safely go back to their normal life. Stefan Lohse and his colleagues have developed a sample pooling testing method involving the pooling of samples before RT-PCR amplification, and only individual samples in the pool with positive results are tested, which can substantially increase test capacity for COVID-19 (Stefan Lohse et al., 2020). Based on their method, Wuhan, a central Chinese city, has tested over 9 million people since May 13 for the coronavirus in 10 days. The mass testing identified 198 asymptomatic carriers and all of them were quarantined (CNN, 2020). Now the city has lifted mass lockdown and is rebooting the citizens’ economic and social life, serving as a good example of post-pandemic recovery. 

Wuhan’s borders were finally reopened on April 8 after 76-day lockdown（CNN, 2020） 

When we have treatable drugs

An increasing number of potential treatable drugs has been introduced since the beginning of the outbreak. Remdesivir is among the most promising. It is an experimental virus blocker made by Gilead Sciences that is now in clinical trials and the result could be in hand by this summer (Yeming Wang et al., 2020). Besides, some previous palliative drugs such as chloroquine phosphate, hydroxychloroquine and azithromycin have been proved to be apparently efficient and acceptably safe against COVID-19 associated pneumonia in multicenter clinical trials conducted in China (Jianjun Gao et al., 2020; Philippe Gautret et al., 2020). The other strategy to develop a treatable drug is to copy the body’s solution (to produce antibodies) to fight pathogens. According to a recent report, llama antibody has been successfully engineered to block coronavirus (Daniel Wrapp et al., 2020). Coronaviruses have been found to be decorated with a spike glycoprotein on their surface (Berend Bosch et al., 2003). Daniel’s team injected a llama with forms of the viruses’ spike proteins, harvested the antibodies from the llama bloodstream, and then engineered new laboratory antibodies that could bind to the spike protein and prevent the virus from entering cells. This is one of the earliest antibodies known to neutralize SARS-CoV-2. Nevertheless, there is still a long distance to go from the products in the laboratory experiments to actual antibody drugs in the clinic trails. A faster solution may come from a company named Regeneron, which has been tapped to develop an antibody drug for Ebola before. The CEO of the company told American President Donald Trump on March 2, “We anticipate, if all goes well, 200,000 doses per month can come out of our factory in New York, starting in August” (A meeting at the White House, 2020).

When a vaccine is developed for widely implementation

Vaccines, offering active acquired immunity to a specific infectious disease, are a relative effective way to really increase safety dramatically. Currently there are 10 candidate vaccines undergoing clinical evaluation and 126 candidate vaccines in preclinical evaluation according to a document published by WHO on June 9 (WHO, 2020). Countries around the world are racing to find a vaccine to halt the COVID-19 pandemic. On May 13, a joint team comprising researches from USA and UK reported their investigational data of ChAdOx1 nCoV-19 vaccine on monkeys, showing that a single vaccination with ChAdOx1 nCoV-19 can protect rhesus macaques against COVID-19 related pneumonia (Neeltje Doremalen et al., 2020). Based on that result, the candidate vaccine has been used in healthy volunteers in a phase I clinical trial started on April 23. On May 18, an American biotech company Moderna announced positive interim Phase 1 data for its RNA-based vaccine candidate mRNA-1273 (Moderna, 2020). Several days later, a Chinese biological company, CanSino Biologics, published its vaccine data showing the immunogenicity of adenovirus type-5 vectored COVID-19 vaccine in human body (Fengcai Zhu et al., 2020). That’s the first published Phase I trial data from any Covid-19 vaccine. To date, there are 2 American vaccines and 5 Chinese vaccines under Phase II trials.  Nevertheless, it still takes 6 months at a minimum to produce and use those vaccines in a large scale all over the world.

Several candidate vaccines in clinical evaluation (WHO, 2020)

When everyone can take an antibody test

How can you know if you are really immune even after vaccination? Libby Pellegrini, a medical expert, holds the view that widespread antibody testing is the key for individuals to really safely re-engage (Libby Pellegrini, 2020). Antibodies, produced several days after the body’s encountering a pathogen, can target at the virus and neutralize it, thus having the potential to work as a temporary vaccine (Balamurugan Shanmugaraj et al., 2020). A person can be let back out into society even in highly contagious areas as long as the person has the ability to take a blood test and know he or she has made antibodies to COVID-19. Theoretically speaking, if all the individuals in a society can be determined to have developed the antibodies, there is no need to keep a social distance anymore. Besides, the results of antibody tests can also be used in contact tracing and infection rate determination. On May 21, realizing antibody tests are useful epidemiological tools, UK Health and Social Care Secretary, Matt Hancock announced plans to roll out more than 10 million SARS-CoV-2 antibody tests (Talha Burki, 2020). Testing on such a large scale depends on fast and user-friendly test tools. On May 15, Duke-NUS, GenScript, and Diagnostics Development (DxD) Hub, A*STAR launched first-in-the-world SARS-CoV-2 serology test to detect neutralizing antibodies. The novel cPass™ SARS-CoV-2 Neutralization Antibody Detection Kit was announced to obtain the CE-IVD mark on May 26 (GenScript, 2020).

Researchers from all over the world have achieved some positive results of studies on diagnosis, prevention and treatment solutions for COVID-19. However, the challenge remains to put an end to the pandemic. 

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