Below, our scientists take scientific papers and rewrite the findings into easily digestible answers. Click on a title to see the summary underneath. Have questions not answered below? You can ask more questions to our scientists on our Ask A Scientist page.
The airborne lifetime of small speech droplets and their potential importance in SARS-CoV-2 transmission
New research has shown that talking loudly can cause the airborne spread of SARS-CoV-2, the coronavirus responsible for COVID-19. People infected with SARS-CoV-2 probably expel more virus into the air when speaking loudly than when speaking softly, and can even just breathe out virus. Virus is ejected into the air via thousands of droplets that are all different sizes. The new study estimates that a person infected with SARS-CoV-2 who speaks loudly for one minute produces at least 1,000 virus-containing droplets that remain airborne for more than 8 minutes. The droplets could be inhaled by others, starting new infections. Considering people can unknowingly be infected with SARS-CoV-2 and spread the virus through the air, it is critical that we all wear face coverings and maintain our distance from one another.
Claims that 5G is linked to, or the actual cause of, COVID-19 are inaccurate
Claims that the coronavirus is spreading using the 5G network or the electromagnetic spectrum do not have any scientific basis. Viruses are made up of biological materials (like proteins and nucleic acids), and cannot be transmitted through radio waves or mobile networks. The World Health Organization has reiterated that COVID-19 is spread when an infected person coughs, sneezes, or talks close to others, and that the disease has spread in many countries without 5G mobile networks.
Non-ionizing 5G radio waves make up a 5G network and travel between mobile phones and cell phone towers. The key difference between 5G radio waves and other wireless networks is that they operate in low, mid, and high microwave bands. While 5G radio waves are a form of radiation, and it is true that some types of electromagnetic radiation have been shown to cause some health problems, non-ionizing 5G radio waves are not harmful to human health. 5G radio waves are similar to the radio waves in any other cell phone, and radio waves, no matter the frequency or source, cannot transmit a virus.
The theory specifically relating 5G radiation to COVID-19 seems to be linked to another inaccurate claim that 5G and other electronics, including cell phones, can emit carcinogenic radiation. This has been based on limited evidence, and the American Cancer Society stated that “the RF (radio frequency) waves given off by a cellphone simply do not have sufficient energy to damage DNA or cause heating in body tissues.”
Though conspiracy theories about 5G, Wi-FI, 4G, and other radio waves have long existed, in 2019, a Florida physicist caused a new wave of skepticism towards the technology by inaccurately claiming that increased frequency waves could damage brain tissue.
The coronavirus-specific theory originated on a French conspiracy website and was based on the recent 5G tower installations in Wuhan around the time of the start of the outbreak. Also in January, a Belgian newspaper shared a headline news story claiming that 5G is life-threatening, but later deleted the article.
Many variations of this conspiracy theory are now circulating, including:
5G suppresses the immune system and increases the impacts of COVID-19;
5G causes radiation and triggers COVID-19;
5G installation is the cause of recent illness, and COVID is a cover-up, and;
5G and COVID-19 are joint efforts to depopulate the Earth.
Specific claims include a correlation between COVID-19 cases and 5G tower installation. Maps seem to show that cases spread in the same cities with 5G deployment in early 2020. 5G was initially deployed in major cities; similarly, COVID-19 spread from Wuhan to large cities because of their high populations and travel – first in China, then around the world. Thus, COVID-19 transmission patterns seemed to mimic the pattern of 5G deployment, however, this is purely correlation with no causality.
Currently, propaganda about 5G networks causing COVID-19 have contributed to public outrage, for example, 5G towers that have been set on fire. This causes unnecessary harm to those exposed to the fire and vandalism, and also could prevent access to cellphone networks for those who are isolated due to the COVID outbreak.
Note: many sites make references to the sources of the original conspiracy theories, but do not link to fake news sites.
Unsubstantiated theory that the COVID-19 novel coronavirus was made in a lab debunked by study
Unsubstantiated theories about the COVID-19 novel coronavirus being created in a lab were fanned when a study (posted online and later retracted) implied that four parts of HIV, the virus that causes AIDS, could have been engineered into the COVID-19 virus.
On Friday, February 14th, a group of researchers published a paper that adds to the scientific evidence debunking the conspiracy theory.
The researchers confirmed earlier scientific reports that the COVID-19 virus is most closely related (96% identical) to a coronavirus that was previously identified in bats. It further provided evidence for why parts of HIV-1 were not incorporated into the COVID-19 virus.
The researchers show that the COVID-19 virus most likely evolved from bat coronaviruses, and that it has not been engineered with 4 parts of HIV-1.
First, three out of the four COVID-19 virus parts in question are found in three other coronaviruses that had been previously isolated from bats, suggesting an evolutionary linkage.
Second, when these four DNA parts are compared to the DNA of other species, researchers found that these DNA parts are also found in the DNA of mammals, insects, bacteria, and other coronaviruses. That means these DNA elements are found throughout the evolutionary tree and are not unique to HIV-1.
Currently scientists are working around the clock to determine which animal was the original host of COVID-19 and which mutations the virus obtained that enabled it to infect humans.
Read NIH director Dr. Francis Collins’ synopsis of a recent article that provides strong scientific evidence that this novel coronavirus arose naturally.
Paper explores the characteristics of COVID-19
A paper published by the Chinese Center for Disease Control (China CDC) analyzes the characteristics of all the COVID-19 cases reported to China’s Infectious Disease Information System. This included over 72,000 patient records with 44,672 confirmed cases. Almost 81% of the cases had mild symptoms. About 8,500 cases out of the over 44,600 that were confirmed had severe or life-threatening symptoms. This paper was written to explain how the virus behaves and help develop effective control strategies to prevent others from getting sick.
According to the data, most of those infected (77.8%) with COVID-19 were between 30 and 69 years old. In China’s population overall, about 57% of the population is within this age bracket. The virus had a fatality rate of about 2.3% and most fatalities occurred when the patients had other severe health issues, such as diabetes, hypertension, or cardiovascular disease. The highest rates of fatalities occurred in patients 60 years and older. This rate is lower than the other notable coronavirus epidemics, Severe Acute Respiratory Syndrome (SARS) and Middle East Respiratory Syndrome (MERS), which had fatality rates of about 11% and 34.4%, respectively. However, COVID-19 is estimated to be more contagious. The number of people a sick person could infect, otherwise known as R0, is how scientists determine how contagious a disease can be. The R0 for SARS and MERS are three and less than one, respectively, and COVID-19’s estimated R0 is about 3.28.
The researchers stated that the data was consistent with the current theory of how COVID-19 originally spread from animals at a Wuhan seafood market. Additionally, they noted that its high rate of mutation allowed it to become infectious to humans and get increasingly efficient at being spread to others. Nevertheless, the authors suggested that the rates of infection are currently slowing. The data show that the number of confirmed cases likely peaked around February 1 and the rate of cases since then has declined. This decline, the researchers explained, could be attributed to the extensive information campaigns from national and international health organizations and the restriction of individuals’ movement between affected cities.
Therapeutic options for COVID-19
While pharmaceutical companies and government agencies have focused efforts on sequencing the genome of COVID-19 and creating vaccines as a response to the outbreak, existing antiviral agents, specifically those developed to treat HIV, hepatitis/C and influenza, have also demonstrated potential to treat COVID-19. Similar therapeutic approaches were effective in treatment of SARS and MERS, other human coronaviruses.
Vaccine development and public uptake is estimated to take months to years, and repurposing existing antiviral agents could more urgently contain the outbreak.
Initial analysis of COVID-19 genomic sequencing demonstrate similarities between the four nonstructural proteins and the spike protein that are served as targets for SARS and MERS treatment.
A type of antiviral called nucleoside analogues (favipiravir and ribavirin, which are approved, and remdesivir and galidesivir, which are experimental) can block RNA synthesis in coronaviruses, and are being studied in Randomized Control Trials for COVID-19 treatment. Reports have demonstrated the ability of another type of drug called protease inhibitors (disulfiram, lopinavir and ritonavir) to block SARS and MERS, though clinical trials have not yet proven effectiveness. Griffithsin, another type of therapeutic, can also target spike glycoproteins, and should be evaluated for effectiveness in COVID-19.
Finally, another class of drugs called pegylated interferons, used in hepatitis B/C treatment, in combination with a nucleoside compound could attack COVID-2019, but would require evaluation for safety. Other small molecules approved for treatment of non-coronavirus diseases could also be assessed and evaluated for effectiveness.
Upcoming needs for COVID-2019 response include screening of existing MERS and SARS inhibitors and optimization of their activities against COVID-2019.
Unsubstantiated COVID-19 novel coronavirus lab-made bioweapon claims fly in the face of science
Unsubstantiated claims about the source of the COVID-19 novel coronavirus – that it is a bioweapon, or that it was made in a lab – are contradicted by research produced by the science community pointing to transmission of the COVID-19 virus from animals to people.
Researchers have found that three quarters of new or emerging diseases that infect people are transmitted to us from animals. For example, the Middle East Respiratory Syndrome (MERS) virus was probably transmitted to people from camels in the Arabian Peninsula, and the Severe acute respiratory syndrome (SARS) virus may have come from bats, or a different animal reservoir, before spreading to civet cats, and then to people in southern China. Viruses are capable of spilling over from animals to people largely because their genetic information mutates, or changes, quite readily.
Scientific evidence suggests the COVID-19 virus also spilled over from animals to people. One paper showed that the COVID-19 virus is 96% genetically identical to a coronavirus that was previously identified in bats, and researchers are working to discover even closer coronavirus matches in animals to home in on the path of spillover into people. Two preliminary studies indicate that the COVID-19 virus could have passed through pangolins (“scaly anteaters”). As more research is conducted, the transmission chain of the COVID-19 virus will become clearer.
During this concerning outbreak of COVID-19 virus, it is tempting to speculate about the source of the outbreak, or give credence to sensational claims. However, to participate in an effective response to the outbreak, it is best to rely on research findings based on science.
Principles of the CDC COVID-19 novel coronavirus test kit
The CDC COVID-19 virus test kit, named the CDC 2019-nCoV Real-Time RT-PCR Diagnostic Panel, initially sent to public health laboratories is based on the principles of molecular biology. Since the COVID-19 virus’ genetic material is made up of ribonucleic acid (RNA), the virus can be detected using a method relying on short deoxyribonucleic acid (DNA) strands designed to attach to the virus’ RNA.
The CDC test kit consists of two mixes (N1 and N2) of short DNA strands that specifically detect the COVID-19 virus, a mix (N3) of short DNA strands that detect severe acute respiratory syndrome (SARS)-like coronaviruses, a mix (RP) of short DNA strands that detect the human gene RNase P, and a sample (nCoVPC) that contains noninfectious lab-synthesized COVID-19 virus N gene RNA as well as human RNase P DNA. Mixes N1, N2, and N3 should all be able to detect the COVID-19 virus. Mix RP should be able to detect the human gene RNase P and be used to evaluate the quality of specimens from patients. Sample nCoVPC should allow lab professionals to check if the test is working properly.
Because COVID-19 virus RNA would be present in relatively low amounts in samples from patients, like those collected by nasal swabs, the amount of nucleic acid that denotes viral presence needs to be boosted in order for it to be detected. This is done using a technique called real-time reverse transcriptase (RT)-polymerase chain reaction (PCR) that amplifies and monitors nucleic acid from initial COVID-19 virus RNA. Real-time RT-PCR reads out viral RNA into DNA, and then copies the DNA over and over again, generating a detectable signal if the specimen contained COVID-19 virus. Mixes N1, N2, and N3 consist of DNA primers that enable read out and copying, as well as DNA probes whose dyes enable the production of a fluorescent signal. In theory, a single copy of the COVID-19 virus RNA genome is detectable by real-time RT-PCR; in practice, coronaviruses need to replicate in order for there to be enough genetic material that can be used for the test.
The fluorescent signals that are produced over the course of the test are tracked and measured by sensitive instrumentation and a specialized software package. As long as controls – intended to be studied side-by-side with specimens potentially harboring COVID-19 virus RNA – perform as expected, showing that the test is working properly, a specimen is designated as positive if all three signals produced from its RNA being separately mixed with N1, N2, and N3 cross a carefully set threshold value.
A mandarin orange in Malaysia was not infected with the COVID-19 novel coronavirus
A false story that a mandarin orange was infected by the COVID-19 novel coronavirus and was then eaten by a prisoner shortly before their death was shared widely in Malaysia, where misinformation about the COVID-19 outbreak has been particularly pervasive.
There are no coronaviruses known to infect mandarin oranges, and no coronaviruses known to infect any plant. Out of hundreds of known coronaviruses, most spread among animals, and seven, including the SARS (severe acute respiratory syndrome), MERS (Middle East respiratory syndrome), and COVID-19 viruses, are known to be able to make people sick. The SARS, MERS, and COVID-19 viruses all spilled over from animals to people. It is estimated that throughout Southeast Asia alone, additional thousands of yet-to-be-discovered coronaviruses are present in bats.
Plants and animals are both made up of building blocks called cells, and to infect a plant or animal, a virus must enter a cell and direct more copies of itself to be made; then, the virus copies must exit the cell. However, plant and animal cells are different, so viruses are typically adapted to either plants or animals. For instance, viruses that infect plants code for a ‘movement protein’ that is needed for the virus to spread throughout the plant, and the COVID-19 virus’ genome does not code for a movement protein. Since some viruses evolve along with plants and some evolve along with animals, a virus that evolves and becomes specialized to infect both plants and animals would be atypical.
Lessons from the SARS, MERS, and other novel coronavirus epidemics
Researchers evaluated the SARS, MERS, and novel coronavirus (COVID-19) epidemics to determine what areas of preparedness need improvement. They studied the Centers for Disease Control and Prevention (CDC) website and PubMed database during each outbreak and found several interesting points. Specifically, the COVID-19 virus spread more quickly because of increased globalization, inadequate assessments of the virus’ urgency, and limited reporting of cases within China. The Chinese government waited almost two months from the first official case to implement travel restrictions, which allowed millions to travel through the virus hot zone unaware of the risk. Similar timing issues occurred during the 2002 outbreak of SARS and added to panic surrounding the disease. MERS did not spread as effectively between people but the biggest challenge was the difficulty of controlling the infections that were already ongoing. To mitigate the spread of the current coronavirus and to prepare for future outbreaks, the researchers suggest encouraging hand hygiene, isolating infected individuals in properly ventilated hospitals, and preventing contact with suspected animal hosts by reducing the number of live animal markets.
Coronavirus infections in infants
This paper examined the cases of nine infants in China who were infected with the novel coronavirus to better understand how it affected children. All of the infants’ families had at least one member who was also infected with the COVID-19 virus. None of the cases required intensive medical care and one had no symptoms of COVID-19 but had tested positive for the virus. Because the infants all had family members with the virus, the researchers recommended that families with babies and sick individuals should take steps to monitor their babies’ health and reduce virus transmission. This includes requiring adult caretakers to wear masks to prevent them from spreading the disease to the infants, wash their hands before coming into close contact with infants, and sterilize baby toys and tableware regularly.
Determining the incidence of infection on the Diamond Princess cruise ship
A researcher studied the rate of COVID-19 infections on the Diamond Princess cruise ship to better understand how the novel coronavirus spread. One of the most difficult parts of predicting the spread of illness is determining the timing of initial infection. To study this, the author used a back-calculation method which started with the total number of cases on February 24 and worked backwards to figure out when the spread first began. From this calculation, the author found that the highest rate of infection was between February 2 and February 4, right before movement restrictions were instituted. However, after the passengers disembarked, some started experiencing symptoms of the virus, even when they did not have any close contact with infected individuals. Because of this, the author recommends studying other modes of virus transmission, such as from asymptomatic individuals and from the environment.
Environmental contamination by patients with COVID-19
To find out how the novel coronavirus could spread, researchers took samples from the isolation rooms of three patients at a designated outbreak center in Singapore. Samples from two patients were taken after routine cleaning and the third sample was taken prior to cleaning. The samples taken after the cleanings did not contain virus particles. The third sample before cleaning the patient’s room had several positive results. Positive samples were found in the bathroom sink and toilet bowl, as well as on vents in the room. This suggests that it may be possible to transmit the virus through contact with stool. However, the researchers did not test to see if the virus particles they retrieved were capable of infecting another person. Nevertheless, the study emphasizes that strict environmental and hand hygiene is important to limit the spread of the novel coronavirus.
A discussion regarding whether the COVID-19 virus is airborne