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Coronavirus COVID-19 Science

Coronavirus: Updates, Symptoms, and Research Findings

Symptoms and latest advances in the biology of the Coronavirus Disease 2019 (COVID-19).

March 23, 2020

SARS-CoV-2 illustration. CDC/ Alissa Eckert, MS; Dan Higgins, MAM / Public domain.

Symptoms and latest advances in the biology of the Coronavirus Disease 2019 (COVID-19).

Last Updated: 4:15 PM GMT July 13, 2020

Life around the world has changed, with billions of people facing unprecedented restrictions. Governments are panicking as grim models project hundreds of thousands of deaths. While uncertainty is sweeping the globe, scientists around the world are scrambling to learn more about the Coronavirus Disease 2019 (COVID-19).

  • SARS-CoV-2, the virus which causes COVID-19, is detectable for up to 3 hours in aerosols, and up to 3 days on plastic and stainless steel, according to a new study published in The New England Journal of Medicine.
  • Another study published in the journal Emerging Infectious Diseases that examined 468 confirmed cases of COVID-19 has found that 12.6% of the infected patients were infected by someone who had the virus but did not yet show symptoms. See more studies below.

Confirmed cases of the coronavirus disease have risen sharply and spanned the globe.

Worldometer’s algorithms have recorded more than 13,125,000 known COVID-19 cases and over 573,000 deaths as of 4:15 PM GMT July 13, 2020.1

See John Hopkins’ COVID-19 interactive map here.

The USA, Russia, Spain, UK, and Brazil — in order— are the top 5 hardest-hit countries so far.

According to the World Health Organization (WHO), only around 1 out of every 6 people who get infected become seriously ill, and about 80% of people recover without medical intervention.

Find some of the latest research breakthroughs in understanding the biology of COVID-19 below.

See near-realtime global COVID-19 cases and deaths estimates here.

See all US Centers for Disease Control and Prevention (CDC) guidelines here.

See all the WHO COVID-19 daily situation reports here.

Find all WHO updates on the COVID-19 outbreak here.

Table of Contents

What is Coronavirus Disease 2019 (COVID-19)?

The coronavirus (COVID-19) is a highly contagious disease caused by Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Brief History of COVID-19

COVID-19 was first identified in Wuhan, a city in Central China in late 2019, and was reported to the WHO by the Chinese authorities on December 31, 2019.2

The first known case has been traced back to November 17, 2019.3

The WHO characterized COVID-19 as pandemic on March 11, 2020.4

Check out the gallery below

Hazardous child labourer with a prosthetic (fake) eye at Agbogbloshie, Ghana. © 2020 Muntaka Chasant

Urban Poor Boy With Prosthetic Eye

See portraits of Kwaku Debrah, a 15-year-old poor urban boy with a prosthetic eye, and how he navigates Accra’s tough urban terrains.

What are the symptoms of COVID-19?

Common symptoms according to the WHO5 include:

  • Fever
  • Tiredness
  • Dry Cough

According to the US CDC, symptoms of COVID-19 may start to appear between 2 to 14 days after exposure, and they include trouble breathing, pressure in the chest, and bluish face or lips.6

Other minor symptoms include runny nose, nasal congestion, and diarrhea.

People of all ages are at risk, but older adults and people with underlying medical conditions such as diabetes, asthma, and heart disease, are at a higher risk for severe illness.

How does COVID-19 spread?

According to the US CDC7 8, COVID-19 is now spreading from person to person through respiratory droplets.

To prevent spread, the WHO has urged people to maintain at least 3 feet distance between themselves and people who are coughing or sneezing.

How To Protect Yourself From COVID-19

  • Both the US CDC and the WHO strongly advise against having close contact with people who are sick. Keep space between yourself and others.
  • Frequent hand washing — for at least 20 seconds — with soap and running water is also strongly recommended. Hand sanitizers that contain at least 60% alcohol should be used in situations where soap and water are not available.
  • The WHO advises against touching eyes, nose, and mouth, especially with unwashed hands.

Clean and disinfect touched surfaces such as doorknobs, light switches, handles, faucets, and keyboards. Also avoid sharing personal household items such as spoon and cups.

Do Face Masks Protect Against COVID-19?

Face masks are not foolproof, but contrary to some of the information out there and giving what we know so far about COVID-19, yes, the right face mask — worn correctly — can reduce the wearer’s exposure to the virus. This should complement other hygiene measures.

Note: The WHO and the US CDC’s holdouts on masks were not based on science. They urged people to save masks for caregivers and other front line medical workers due to supplies running low.

Proper fitting respirators — airtight and snug — that have been lab-certified (such as N95, FFP2, KN95, P2, etc.) are effective at filtering out the tiny airborne particles they are designed to block.

Only putting on the mask is not enough at all. It should fit snugly and securely without air leaks around the edges. Always adjust for a good fit (such as the nose clip for a hermetic seal) or find a mask that works for your face.

Avoid loose-fitting masks in COVID-19 high-risk environments.

The Occupational Safety and Health Administration (OSHA) still does not approve the use of surgical masks in high hazard (aerosol-generating) procedures. 

OSHA recommends the use of certified powered air-purifying respirators (PAPRs) for high-hazard environment.

Most surgical masks are designed to catch bacteria from the wearer’s mouth or nose; they do not always protect the wearer from tiny particles and infectious droplets due to how loose they fit.

If local authorities in your area are suggesting you cover your face with makeshift cloth masks, you should know that the idea is to protect others from you (in case you have the virus), and not to protect yourself. There’s no science at all behind this suggestion.

Depending on the fabric/material used, people could be getting zero protection from wearing cloth masks. This could be giving cloth mask wearers a false sense of security.

To minimize your exposure to the virus, wear certified respirators that fit snugly without air leakages.

Strictly follow the fitting instructions in the manual that came with your respirator.

See the WHO interim guidance on the use of masks in the context of COVID-19 here.

What are Some of the Latest Scientific Breakthroughs on COVID-19?

There are already dozens of scientific discoveries on COVID-19, as you can see in the WHO database of publications on COVID-19.

Below are some of the most relevant scientific breakthroughs on COVID-19 so far:

1. Aerosol and Surface Stability of Coronavirus

According to a new study published (March 17, 2020) in The New England Journal of Medicine9 by scientists at CDC, Princeton University, The University of California, Los Angeles, and National Institute of Health, SARS-CoV-2 can be stable for hours to days in aerosols and on surfaces such as copper, plastic, and stainless steel.

SARS-CoV-2 is detectable for up to 3 hours in aerosols, and up to 3 days on plastic and stainless steel, according to the study. This suggests that people may get infected through the air and after touching contaminated surfaces.

See the full study here.

2. COVID-19 has Natural Origin; not Man Made

A new study — published on March 17, 2020, in the journal Nature Medicine10 — by scientists at the Scripps Research Institute has found no evidence that COVID-19 was engineered or man-made in a laboratory.

The researchers analyzed public genome sequence data from SARS-CoV-2. They found that the receptor-binding domain portion of the virus spike protein had evolved to target the enzyme Angiotensin converting enzyme 2. The finding points to natural selection, not genetic engineering, the scientists concluded.

Read the study here.

3. Coronavirus Sometimes Spread Before People Have Symptoms

Scientists at the University of Texas at Austin have identified how quickly the coronavirus can spread in a new study published in the journal Emerging Infectious Diseases.11

The researchers examined 468 confirmed cases of COVID-19 and found that 12.6% of the infected patients were infected by someone/people who had the virus but did not yet show symptoms.

“This provides evidence that extensive control measures including isolation, quarantine, school closures, travel restrictions and cancellation of mass gatherings may be warranted,” said Lauren Ancel Meyers, one of the researchers.

Read the full study here.

4. Incubation Period for COVID-19

Stephen Lauer and other researchers studied 181 confirmed cases and estimated the median incubation period for COVID-19 to be approximately 5 days. They found that 97.5% of people who develop symptoms will do so within 11.5 days, implying that around 101 out of every 10,000 cases will develop symptoms after 14 days of active monitoring.

This study was published in the Annals of Internal Medicine12. Read it here.

5. Undocumented Infection Accelerating The Spread of COVID-19

Scientists at Columbia University Mailman School of Public Health have found in a new study that undocumented cases were responsible for the fast spread of COVID-19 outbreak in China13, underscoring the pandemic potential of SARS-CoV2.

According to the study, 86% of all cases were undocumented before January 23, 2020, Wuhan travel restrictions. The study found that undocumented infections were 55% of documented infections and the infection source for 79% of documented cases.

“The explosion of COVID-19 cases in China was largely driven by individuals with mild, limited, or no symptoms who went undetected,” says Jeffrey Shaman, co-author of the study.

“Heightened awareness of the outbreak, increased use of personal protective measures, and travel restriction have helped reduce the overall force of infection; however, it is unclear whether this reduction will be sufficient to fully stem the virus spread,” Shaman added in a statement.

The study was published in the journal Science. See it here.

6. Camostat Mesilate Drug Found to Block SARS-CoV-2 infection

A study by infection biologists with the German Primate Center has found that the drug camostat mesilate can suppress protease TMPRSS2, an enzyme present in our body, which SARS-CoV-2 uses as a gateway into human cells.

Camostat mesilate is presently approved in Japan for pancreatic inflammation treatment.

“Our results show that SARS-CoV-2 requires the protease TMPRSS2, which is present in the human body, to enter cells,” said Stefan Pöhlmann, one of the co-authors.

Markus Hoffmann, another researcher familiar with the study, added: “Our results suggest that camostat mesilate might also protect against COVID-19.”

See the study here.

7. Old Age & Other Risk Factors Associated with Adult Inpatient Deaths From COVID-19

A new study which studied 191 patients with confirmed COVID-1914 from two hospitals — Jinyintan and Wuhan Pulmonary Hospital — in Wuhan has associated old age and underlying conditions such as diabetes and blood clotting when hospitalized with a higher risk of death from the virus.

“Older age, showing signs of sepsis on admission, underlying diseases like high blood pressure and diabetes, and the prolonged use of non-invasive ventilation were important factors in the deaths of these patients. Poorer outcomes in older people may be due, in part, to the age-related weakening of the immune system and increased inflammation that could promote viral replication and more prolonged responses to inflammation, causing lasting damage to the heart, brain, and other organs,” said Dr Zhibo Liu, one of the co-authors. 

The study was published in The Lancet. Read the full study here.

8. First known person-to-person transmission of SARS-CoV-2 in the USA

A new study published in The Lancet15 has documented the first known locally-transmitted case of SARS-CoV-2 from a woman in her 60s who had returned from China around mid-January, 2020, to her husband, who had not traveled with her but had frequent contact with her.

The woman, codenamed Patient 1, tested positive for SARS-CoV-2 a week later. Her husband (Patient 2), who had not traveled to China, but had close contact with her also tested positive 8 days later.

Overall, 372 people were identified as contacts for both cases, but none of them tested positive for SARS-CoV-2 despite active monitoring.

Dr Jeniffer Layden, who co-authored the study said in a statement: “This report suggests that person-to-person transmission of SARS-CoV-2 might be most likely to occur through unprotected, prolonged exposure to an individual with symptomatic COVID-19.”

“Without using appropriate facemasks or other personal protective equipment, individuals living in the same household as, or providing care in a non-healthcare setting for, a person with symptomatic COVID-19 are likely to be at high risk of infection. Current CDC recommendations for individuals with high-risk exposures to remain quarantined with no public activities might be effective in reducing onward person-to-person transmission of SARS-CoV-2,” Dr Tristan, co-lead author, added.

The study was published in The Lancet. Full text is available here.

9. Personal History of Smoking Linked to the Progression of COVID-19 Pneumonia in China

Factors such as old age, history of smoking, and respiratory failure can contribute to the progression of pneumonia in COVID-19 patients, a Chinese study has found16.

The study was published in the Chinese Medical Journal. See the study here.

10. A Modelling Study Shows Physical Distancing is Effective At Reducing the Spread of SARS-CoV-2 infections

A combination of quarantining infected individuals and their close contacts, workplace distancing, and school closure, is most effective at reducing SARS-CoV-2 infections compared with other intervention designs, a Singapore modelling study17 published in The Lancet Infectious Diseases has found.

“Should local containment measures, such as preventing disease spread through contact tracing efforts and, more recently, not permitting short-term visitors, be unsuccessful, the results of this study provide policy makers in Singapore and other countries with evidence to begin the implementation of enhanced outbreak control measures that could mitigate or reduce local transmission rates if deployed effectively and in a timely manner,” said Alex R Cook, co-author of the study.

Read the full study here.

11. Trial Drug Found To Block Early Stages of COVID-19 in Engineered Human Tissues

A team of scientists has found that a trial drug called APN01 soon to be tested in clinical trials can effectively block the cellular door SARS-CoV-2 uses to infect its hosts.

“We are hopeful our results have implications for the development of a novel drug for the treatment of this unprecedented pandemic,” said Josef Penninger, a co-author of the study.

Art Slutsky, another co-author of the study and a scientist at the Keenan Research Centre for Biomedical Science of St. Michael’s Hospital and professor at the University of Toronto, added: “Our new study provides very much needed direct evidence that a drug — called APN01 (human recombinant soluble angiotensin-converting enzyme 2 — hrsACE2) — soon to be tested in clinical trials by the European biotech company Apeiron Biologics, is useful as an antiviral therapy for COVID-19.”

See more details here.

12. Scientists Announce Potential Vaccine Against COVID-19

Scientists at the University of Pittsburgh have announced a candidate vaccine for COVID-19. The potential vaccine produces antibodies specific to SARS-CoV-2 at quantities that are considered adequate to kill the virus.

The research was published by The Lancet18.

Andrea Gambotto, one of the study co-authors said: “We had previous experience on SARS-CoV in 2003 and MERS-CoV in 2014. These two viruses, which are closely related to SARS-CoV-2, teach us that a particular protein, called a spike protein, is important for inducing immunity against the virus. We knew exactly where to fight this new virus.”

The researchers are now in the process of seeking approval to start clinical trials.

“Testing in patients would typically require at least a year and probably longer,” said Louis Falo, another co-author of the study.

See the full study here.

13. Zero out of 278 infected by COVID-19 After Wearing N95 Mask

A study by researchers at Zhongnan Hospital of Wuhan University in Wuhan has found that medical staff who wore N95 masks did not get infected by COVID-19 compared with a group that did not wear a mask.

The scientists separated 493 medical staff (doctors and nurses) into N95 group (wore N95 masks) and no-mask group (wore nothing).

Results: zero out of 278 (56 doctors and 222 nurses) from the N95 group — disinfected and cleaned their hands frequently — were infected by COVID-19. In contrast, 10 out of 213 (77 doctors and 136 nurses) from the group that did not wear masks contracted the virus. This study underscores the need for N95 level respiratory protection against COVID-19.

Equivalence of N95 includes KN95, P2, and FFP2.

See the study here.

14. Experimental Drug Remdesivir Shows Promise In Treating COVID-19

The condition of 36 out of 53 COVID-19 patients with severe breathing problems has improved after receiving a 10-day course of remdesivir, an experimental drug being developed by Gilead Sciences Inc.

Remdesivir was initially developed to treat the virus which causes Ebola, but was determined to be less effective.

The study was published in the New England Journal of Medicine. See it here.

15. 78% of People Infected With COVID-19 Did Not Show Symptoms

130 of 166 people infected with COVID-19 on April 1, 2020, were asymptomatic, according to China’s National Health Commission. See the brief report here.

16. Presymptomatic COVID-19 Patients Can Spread The Disease – New Study

People infected with COVID-19 can spread — as opposed to symptomatic patients — the deadly disease for close to 2 and a half days before symptoms such as fever, dry cough, and body ache start to appear, a new study published in the journal Nature has found.

Out of the 94 patients with confirmed COVID-19 cases the scientists observed, 77 were documented to have transmitted the virus to other individuals before showing symptoms. See the study here.

17. COVID-19 Patients Still Tested Positive After Symptoms Disappeared

Around 50% (8/16) of patients treated for mild cases of the coronavirus disease remained viral positive for up to 8 days after all symptoms disappeared, according to a new study.

“The most significant finding from our study is that half of the patients kept shedding the virus even after resolution of their symptoms,” said Lokesh Sharma, one of the study’s co-authors.

The study was published in the American Thoracic Society’s American Journal of Respiratory and Critical Care Medicine19.

Lixin Xie, another co-author of the study recommended: “If you had mild respiratory symptoms from COVID-19 and were staying at home so as not to infect people, extend your quarantine for another two weeks after recovery to ensure that you don’t infect other people.”

See the study here.

18. Goblet And Ciliated Cells in The Nose Likely COVID-19 Entry Points

A new study published in the journal Nature has identified goblet and ciliated cells in the nose as having significant levels of certain types of proteins that SARS-CoV-2 uses to get into human cells 20.

“We found that the receptor protein — ACE2 — and the TMPRSS2 protease that can activate SARS-CoV-2 entry are expressed in cells in different organs, including the cells on the inner lining of the nose. We then revealed that mucus-producing goblet cells and ciliated cells in the nose had the highest levels of both these COVID-19 virus proteins, of all cells in the airways. This makes these cells the most likely initial infection route for the virus,” said Waradon Sungnak, one of the paper’s lead authors.

The entry proteins ACE2 and TMPRSS2 were also detected in corneal and intestinal epithelial cells.

Martijn Nawijn, another co-author added: “This is the first time these particular cells in the nose have been associated with COVID-19. While there are many factors that contribute to virus transmissibility, our findings are consistent with the rapid infection rates of the virus seen so far. The location of these cells on the surface of the inside of the nose make them highly accessible to the virus, and also may assist with transmission to other people.”

See the full study here.

19. Loss of Smell and Taste Linked to COVID-19 Infections

Researchers at the University of California – San Diego have associated sensory loss with COVID-19 infections after surveying 1480 patients with influenza-like symptoms.

Carol Yan, one of the authors said: “Based on our study, if you have smell and taste loss, you are more than 10 times more likely to have COVID-19 infection than other causes of infection. The most common first sign of a COVID-19 infection remains fever, but fatigue and loss of smell and taste follow as other very common initial symptoms. We know COVID-19 is an extremely contagious virus. This study supports the need to be aware of smell and taste loss as early signs of COVID-19.”

Loss of smell was reported for 40/59 patients who tested positive for COVID-19. Loss of taste; 42/59 compared to 35/203 of COVID-19-negative patients surveyed.

The study also found high sensory recovery rate.

“Our study not only showed that the high incidence of smell and taste is specific to COVID-19 infection, but we fortunately also found that for the majority of people sensory recovery was generally rapid,” said Yan added. “Among the Covid-19 patients with smell loss, more than 70 percent had reported improvement of smell at the time of survey and of those who hadn’t reported improvement, many had only been diagnosed recently.”

See the study here.

20. Study Finds Correlation Between Vitamin D Deficiency And High COVID-19 Mortality Rates

Researchers at Northwestern University using global data have found a strong correlation between severe vitamin D deficiency and death from COVID-19.

The team analyzed publicly available data from countries such as South Korea, Italy, China, Iran, Switzerland, and the United States. Compared to countries that were not severely affected, patients from countries with high COVID-19 mortality rates, such as Italy and Spain, had lower levels of vitamin D.

“While I think it is important for people to know that vitamin D deficiency might play a role in mortality, we don’t need to push vitamin D on everybody,” said Vadim Backman, one of the researchers.

See the study here.

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© 2020 Muntaka Chasant



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