Debunking COVID-19 prevention rumors, myths
Can garlic, alcohol or salt water prevent COVID-19? Is whether infections with high fever counted as asymptomatic cases? What kind of disinfection is required at home after family members test positive?
Shanghai's official rumor-debunking platform has listed some online rumors and common requests about the COVID-19 prevention, symptoms and treatment. Most of the answers are from medical professionals with the national or the city's COVID-19 treatment experts' team.
Pedestrians, wearing masks, walk past a local resident busy on a laptop.
About COVID-19 prevention
Q: Can garlic, ginger and pepper prevent COVID-19 infection?
A: No.
The World Health Organization clearly stated on its official website that there is no evidence that ginger, garlic, peppers, etc. can prevent the coronavirus, though these foods have certain antibacterial and anti-inflammatory properties.
Q: Can drinking alcohol prevent COVID-19 infection?
A: No.
Though 70-75 percent alcohol can effectively kill the coronavirus, it does not mean "drinking it can kill the virus." Firstly, normal alcoholic drinks can hardly reach such concentration. Secondly, once entering the digestive system, the alcohol (ethanol) will rapidly diffuse, be diluted, absorbed and cannot kill the virus in the body.
Q: Can gargling with salt water prevent COVID-19 infection?
A: No.
There is no research that shows salt water can kill COVID-19. The novel coronavirus mainly invades the respiratory tract that salt water cannot reach via gargling. Gargling with salt water can only help to clean the mouth and throat as well as relieve the symptoms of faucitis.
Q: Can masks be reused after being worn for a certain period of time?
A: No.
The cumulative wearing time of each mask shall not exceed eight hours. Timely replacement is necessary when the mask is dirty, deformed, damaged or smelly. Masks should not be reused after taking long-distance public transport or going to hospital.
Q: Wearing a mask for a long time will cause lung nodules?
A: No.
The increasing number of pulmonary nodules is mainly due to more advanced detection methods and more frequent screening, which has nothing to do with masks.
People wearing N95 masks and facial screen are seen on a local street in Shanghai.
Q: Can the ethylene oxide used to disinfect the mask cause cancer?
A: No.
Ethylene oxide is one of the most important low-temperature sterilization methods at present, and is widely used in food packaging and various paper products. Only inhaling a large amount of ethylene oxide gas will cause poisoning. The masks sterilized by ethylene oxide contain very little amount of the gas and will not affect health.
Q: Can ultraviolet light kill the coronavirus immediately?
A: No.
It takes at least half an hour for a common ultraviolet light to effectively disinfect. It is not recommended at home, because the UV ray is also harmful to the skin and mucous membrane.
Q: Is it necessary to prepare oxygen generators at home to cope with COVID-19 infection?
A: No.
Only infections with severe and critical symptoms need oxygen inhalation, but the home oxygen generator cannot play a therapeutic role. Moreover, if the concentration of oxygen inhalation is too high or the time is too long, it will lead to oxygen poisoning. Oxygen inhalation therapy should be carried out under the guidance of doctors.
Q: Are pregnant women more likely to be infected?
A: No.
The infection rate and symptoms of the Omicron variant are similar between pregnant women and ordinary people. COVID-19 infection won't have any greater impact on the health of maternal women than the general population.
Q: Can taking medicines prevent cold/flu/COVID-19?
A: No.
Medicines cannot prevent the diseases, they only relieve symptoms. Do not take medicines blindly when there are no symptoms. Improper usage can cause side effects as well as liver and kidney damage.
A man does an antigen test at the fever clinic of Longhua Hospital.
About COVID-19 symptoms
Q: Does fever mean COVID-19 infection?
A: Not necessarily.
Both COVID-19 and influenza can cause fever. Some can also be double-infected.
Q: Can someone with high fever of up to 40 degrees Celsius be counted as an asymptomatic case if there is no pneumonia infection?
A: No.
According to China's latest COVID-19 prevention and control protocols, the definition of asymptomatic infection is: 1. positive pathogenic test; 2. no relevant clinical symptoms, such as fever, dry cough, fatigue, pain, decreased sense of smell (taste), diarrhea and other self-perceived or clinically identifiable symptoms; 3. CT image shows no COVID-19 pneumonia features.
Therefore, asymptomatic infection refers to the absence of any obvious symptoms during the entire infection process.
Q: The prevalent COVID-19 strain in Beijing is more virulent than that in Guangzhou?
A: No.
The current COVID-19 pandemic in China is dominated by the Omicron subvariants of BA.5 – the BA.5.2 and BF.7, which are the prevalent ones in Guangzhou and Beijing, respectively. Up to 98 percent of the infections in Beijing have no symptoms, according to statistics.
Q: Does a darker antigen detection line mean more virus in the body?
A: No.
Antigen detection can only tell whether or not there is an antibody, but cannot detect the amount. The concentration of antibodies is not directly related to the viral load, but the immune response of each person.
Q: Does a negative antigen test mean no infection?
A: Not necessarily.
It normally takes two to three days after the infection for an antigen test to turn positive. Some cases, especially those without symptoms, can even take five days or longer to be detected due to the low viral load.
A man takes a polymerase chain reaction (PCR) test at a streetside kiosk in Shanghai.
About COVID-19 treatment
Q: Can infection be equivalent to vaccination and the early the better?
A: No.
After being infected, people will gain immunity against the certain strain within a certain period of time. Omicron is more likely to cause reinfection than Delta and other previous variants. Repeated infection still has a certain risk of severe symptoms, and may infect high-risk groups, such as the elderly at home and those with underlying diseases.
Try to get infected later and less. Protection and vaccination are necessary after recovery.
Q: Is it necessary to go to hospital immediately after infection?
A: No.
About 99.5 percent of infections do not need to go to hospital. People under the age of 80 without underlying diseases or with stable underlying diseases but fully vaccinated are listed as low-risk group. People exempted from the group with symptoms such as high fever should go to hospital for evaluation.
Q: Should I just take the medicines recommended by the National Health Commission during home quarantine?
A: Not recommended.
These medicines are inadequate for severe or critical conditions, which require oxygen therapy, respiratory support, anti-infection, and systemic support treatment.
If there is persistent high fever (above 39 degrees Celsius) or fast pulse (heart rate over 100 beats per minute) for more than three days; or if the oxygen saturation drops below 95 percent, people should go to hospital in time.
If the fever is accompanied by obvious difficulty in breathing, or unrelieved chest pain, then, too, people should go to hospital immediately.
Q: Should I follow online tips to take medicines in order?
A: Not recommended.
There is no absolute and complete order of taking medicines for COVID-19 treatment. The tips contain various kinds of drugs, including western and traditional Chinese medicines. They need to be taken according to their respective effects, not in order.
Q: Can I use antibiotics to treat inflammation when symptoms appear?
A: No.
Antibiotics are useless against flu or COVID-19, so most patients do not need antibiotics. Antibiotics should only be used after secondary bacterial infections are detected after the COVID-19 infection.
Customers buy medicines at a drugstore on Nanjing Road E.
Q: Can I take more medicines to get better faster?
A: No.
Different medicines cannot be used together. Otherwise they may damage the liver. For example, antipyretics and cold medicines cannot be taken together when you have a fever.
Acetaminophen or ibuprofen cannot be used more than four times a day. The interval between each dose of ibuprofen should be six hours.
In addition, Western antipyretics and Chinese cold medicines cannot be used together, because some traditional Chinese medicines have antipyretic effects.
Only one type of TCM cold medicine should be chosen and taken in small quantities multiple times. Otherwise, they may hurt the spleen and stomach.
Q: Should I take antipyretics whenever there is fever?
A: Not necessarily.
Fever is a protective response of the immunity. When the body temperature rises, the immune response will increase accordingly. It is unnecessary to take antipyretics when the temperature is under 38 degrees Celsius, especially where there is no clear diagnosis. Taking antipyretics casually will cover up the condition and interfere with the diagnosis.
A downtown Shanghai shopping mall seems deserted, with few customers.
About daily life
Q: Oranges, cola or alcohol can lead to false positive polymerase chain reaction (PCR) result?
A: No.
If a "false positive" does occur, it is often caused by laboratory contamination, and generally has nothing to do with a person's diet.
However, daily diet may lead to "false negative," because the liquid will dilute the virus particles in the mouth and throat.
It is recommended not to drink water, beverages, or alcohol before nucleic acid tests.
Q: Is there a need for "terminal disinfection" at home after people are infected?
A: Not necessary.
For ordinary families, only special parts need to be disinfected, such as the surfaces of toilet, refrigerator, tables and cabinets, which can be wiped with alcohol wipes or chlorine-containing disinfectant.
Clothes, bed sheets, quilts and other cotton items can be put under sunshine or heated to reduce the activity of the virus.
It is recommended to ventilate 2-3 times a day, and at least 30 minutes each time.
A quarantine staff disinfects a local office in Shanghai after some of the staff got infected.
