The virus, SARS-CoV-2, which causes the disease COVID 19, is one of many coronaviruses. These can cause illness in animals and humans, and they are highly contagious.
According to the World Health Organization, the most common symptoms of COVID-19 are
- dry cough.
However, certain individuals who are infected, may not have any symptoms at all. It is necessary to understand how coronavirus transmits from one person to another. This knowledge would help to protect the vulnerable and limit the spread of the virus. In this article, you would get to learn more about the virus’s potential transmission routes, including whether or not the virus is airborne and some latest news and research on the novel coronavirus.
Can coronavirus spread through air?
Currently, the lead organization working for research and potential vaccines, the World Health Organization or popularly abbreviated as WHO, does not believe that the novel coronavirus is airborne. However, research into the transmission routes of the virus is ongoing. Virologists are still not sure about how exactly SARS-CoV-2 spreads. So far, they have been working from the facts and knowledge they have of other coronaviruses, such as Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS). Experts however, tend to agree that coronaviruses are transmittable through the inhalation of droplets from a person who is infected. Sneezes and coughs expel droplets from the body.
According to the WHO, these droplets are heavy enough that they cannot travel more than around 3 feet (1 meter). However, other research has found they can travel 23–27 feet (7–8 meters). The airborne particles have to be smaller than the droplets to linger in the air for longer. The air currents can even carry them for longer distances.
For example, the measles virus can remain contagious in the air for up to 2 hours. Airborne viruses are the most contagious ones. According to WHO, SARS-CoV-2 is not airborne, but there are other experts who seem to disagree.
Most of the respiratory viruses are contagious when a person has symptoms. However, there is growing evidence which suggests that the virus might also spread during the incubation period. This is the period before a person develops any of the symptoms. The incubation period is the time that elapses between the entering of a virus in the body and the development of symptoms. Experts consider this period to be between 2 and 14 days only for SARS-CoV-2.
The Centres for Disease Control and Prevention or the CDC suggest that the virus spreads:
- through respiratory droplets produced when a person with the infection coughs, sneezes, or talks
- when these droplets land in the mouth or nose of a person who is nearby
- between people who are within 6 feet (2 meters) of each other
It can even be possible a person contracts SARS-CoV-2 by touching a surface that has contaminated droplets on it. Then touching their nose, mouth, or eyes, as these are the gateways for the virus. The World Health Organization suggests that coronaviruses can remain active on certain surfaces for a few hours or even several days. This varies with different conditions, such as the temperature, the type of surface and the humidity.
- The recent coronavirus outbreak was reported in Wuhan, China, in December 2019.
- Known as SARS-CoV-2, the virus has resulted in more than 7 million infections and nearly 404,000 deaths.
- SARS-CoV-2 infection causes a respiratory illness called COVID-19 or coronavirus disease.
- COVID-19 has now been reported on every continent except Antarctica.
Dr. Fauci warns that the deadly pandemic ‘isn’t over yet’:
At a press conference, Dr. Anthony Fauci, the director of the National Institute of Allergy and Infectious Diseases, called COVID-19 his “worst nightmare” and said that how “rapidly it just took over the planet” surprised him. “That’s millions and millions of infections worldwide. And it isn’t over yet.
And it’s condensed in a very, very small-time frame,” said Dr. Fauci on the number of coronavirus cases, in a Fireside Chat session at the Biotechnology Innovation Organization International Convention. He even highlighted that the long-term impact of experiencing severe coronavirus remains unclear.
The total global number of coronavirus cases is 7.4 million, as on June 10, 2020. The exact figure being 7,142,462. The deadly virus has consumed nearly 405,000 lives worldwide. The cases have been increasing consistently in the countries that are already on the top 5 list. The United States has confirmed 1.96 million cases, followed by Brazil with 707,000 cases, Russia with 484,000 cases, United Kingdom with 288,000 cases and India with 267,000 cases.
The US is experiencing relaxations in the lockdown even after a considerable amount of cases being reported in some areas. There was a sudden jump in the cases reported by India after it relaxed certain restrictions. Since then, the country has been experiencing the highest number of cases every day.
The country, however, is not under a complete lockdown as of now. Schools, colleges and educational institutions haven’t been allowed to re-open, and they are expected to resume from late August. On the other hand, the countries that have declared themselves free from the coronavirus are New Zealand, Montenegro, Eritrea, Papua New Guinea, Seychelles, Holy See, Saint Kitts and Nevis, Fiji and East Timor.
WHO revises its statement on asymptomatic transmission:
Comments made in a press briefing suggested that people infected by the novel coronavirus, but don’t experience any of the symptoms are unlikely to pass the virus on. The World Health Organization (WHO) have since clarified that asymptomatic transmission still remains a “big open question.”
In a live question and answer session hosted on social media, Dr. Maria van Kerkhove, the Head of Emerging Diseases and Zoonosis at the World Health organisation, explained that- “somewhere between 6–41% of COVID-19 cases might be asymptomatic”. Her previous comments that asymptomatic transmission of the virus is “very rare” referred to a small number of studies and some unpublished data, she added. She even explained that some studies that use modelling data suggest that 40% of the transmissions of the new coronavirus may be from people who do not show any symptoms, even after being infected.
She highlighted that both the number of asymptomatic cases and the rate of transmission from these individuals remains an open question. “Whatever proportion of the disease transmits from asymptomatic individuals, that is unknown, and that is occurring, I’m absolutely convinced that that is occurring. The question is how much,” Dr. Mike Ryan, the Executive Director of the WHO’s Health Emergencies Programme, stated at a press briefing.
Study suggests that COVID-19 tests miss a significant number of cases:
According an existing studies, coronavirus PCR tests have a false negative rate of at least 20%. This means that 20% of people who have the new coronavirus receive a negative test result. The research team, from Johns Hopkins University in Baltimore, in Maryland; analysed seven studies that included data from 1,330 patient samples. The team found out that the rate of false-negative results depended on the time since infection. The authors estimate that nearly 4 days after acquiring the virus, a staggering 67% of people would have a false negative result. The rate is similar at 3 weeks.
Around 8 days post infection, which is nearly 3 days after the average time that symptoms start, is the most accurate time to test the individual. However, around 20% of people would still have a false negative result.
Were there COVID-19 cases in China as early as last August?
A new study, that has not yet undergone peer review, suggests that hospital visits and online searches for coronavirus symptoms go back as far as August 2019 in Wuhan, China. Chinese officials do not agree with these statements and findings. A study, by researchers from Boston University and Harvard Medical School, analysed satellite images of hospital parking lots in Wuhan in combination with an internet search history of the term “cough” and “diarrhoea”.
The team explained that while internet searches for the term “cough” naturally fluctuates in line with the flu season, searches for the term “diarrhoea” do not follow the same pattern in any way. The researchers report a spike in searches for “diarrhoea” in the month of August in 2019. While they do acknowledge that their work has several limitations, they concluded that “these findings also corroborate the hypothesis that the virus emerged naturally in southern China and was potentially already circulating at the time of the Wuhan cluster.”
“I think it is ridiculous, incredibly ridiculous, to come up with this conclusion based on superficial observations such as traffic volume,” said the Chinese Foreign Ministry spokeswoman Hua Chunying, commenting on such findings in a press conference.
The origin of the new virus is however, still a mystery as there have been several allegations made that it leaked from a laboratory in Wuhan. This statement has no strong evidence yet and the World Health Organization, with the help of the Governments of several countries are carrying out researches and working tirelessly to develop a vaccine for this deadly virus.