Wearing a mask is the best protection, the efficacy of spraying a spray on epidemic prevention is doubtful

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(Hong Kong News) Can you prevent infection by taking off your mask when eating out or exercising? Or just a false sense of security?

Clinical studies have not been completed

◆ Nitric Oxide

Research on nasal and oral sprays related to the new coronavirus is in full swing, including nitric oxide nasal spray, which is in the third phase of clinical research for the prevention of new coronavirus infection.

Family doctor Lin Yonghe reminded that although nitric oxide may inhibit the new coronavirus in the same way that it inhibits the SARS virus, the exact mechanism of action against the new coronavirus is not yet clear. Clinical research has not been completed, and the product effect is yet to be confirmed.

Other studies have shown that the level and bioavailability of nitric oxide in patients with coronary disease are low, and external supplementation of nitric oxide may help prevent or treat new crown infection; inhaled nitric oxide (iNO) has a lot of research on the treatment of coronary disease, but A safe and effective dose is unknown.

He noticed that most of the research on nitric oxide and COVID-19 is aimed at treatment, such as the combination of nitric oxide and antiviral drugs as a potential option for the treatment of COVID-19; whether it can be used to prevent COVID-19 infection is debatable.

◆Echinacea Extract

Some oral sprays contain echinacea extract, and the product indicates that echinacea has anti-inflammatory and anti-viral effects. He cited studies showing that soaking echinacea in tea bags can improve cold symptoms; in addition, there are also studies showing that echinacea lozenges can prevent upper respiratory tract infections.

“However, there is currently no research or clinical data on echinacea in the prevention of coronavirus infection. Whether echinacea can be used as a virus preventive agent, treatment adjuvant, and immune enhancer for high-risk groups remains to be further studied.”

He reminded that the research effect of a certain substance may only be aimed at the oral effect, and the research results cannot be applied to other dosage forms. For example, oral capsules of a certain ingredient are useful, but it does not mean that the spray has the same effect.

◆Other ingredients

Some nasal sprays use carrageenan, which claims to be scientifically proven to inhibit the new coronavirus, and the product is listed as “US FDA product certification”. However, the ability to suppress the virus does not necessarily correlate with effective prevention of infection or alleviation of disease.

On the other hand, for a product to enter the US market, medical manufacturers need to register the product (establishment registration) and list the product (device listing), but this does not mean that the US FDA approves that the product can achieve its claimed effect.

Clinical research resources are huge

Carrageenan, xylitol, and hypromellose are common ingredients in nasal and oral sprays. Studies have tested the antiviral effects of these ingredients on the new coronavirus.

Dr. Liang Zichao, a specialist in respiratory system, reminded that the results of in vitro experiments are not enough to reflect the clinical utility.

“To prove that the spray is effective, we must first test whether it can block the virus-infected cells in a test tube, then conduct animal experiments, and finally clinical research. At present, some sprays have been tested on animals, and some have not yet entered the clinical stage or progress is slow.”

“In addition, there are difficulties in the clinical research of preventive drugs. Since there is one communicator for every 100 to 1,000 people, a large number of groups are required to conduct preventive research, which in turn requires considerable resources to be invested, making research and development more difficult. Furthermore, to be widely used in the population, the safety concerns of sprays are particularly high, especially for inhaled products or drugs, which must be approved for clinical research before they can be widely used, and it seems that it will still take some time.”

The spray only covers the nasal mucosa

In addition, the spray itself has certain limitations. “More and more evidence has found that the new coronavirus is often transmitted in the air through fine aerosols. In addition to the mucous membranes of the nose, eyes, and mouth, it may also infect the entire respiratory tract, including the trachea, bronchi, and alveoli. Up to 100 square meters, equal to the size of a thousand-foot mansion!”

Liang Zichao said that the spray that only covers the nasal mucosa may not be able to completely block the virus from invading the body.

He pointed out that even if the spray can fully cover the infected area, it must ensure that the active ingredients can stay in order to play a role. Due to the self-cleaning function of the respiratory tract, the fluff and secretions inside will expel foreign substances from the body, making it difficult for the spray to adhere to the respiratory mucosa for a long time.

Lin Yonghe also pointed out that virus droplets can contact the mucous membranes of the eyes, mouth, and nose, and the spray has protective loopholes. Breathing and runny nose will take away the ingredients of the nasal spray, which may not stay in the nasal cavity for a long time to achieve the preventive effect. In addition, it is unknown whether the product is waterproof, so it may not be suitable for swimming.

or create a false sense of security

“Although the efficacy of the current products is questionable, relevant research is worthy of support, or it may really help the epidemic in the future.”

Lin Yonghe believes that wearing a mask properly is the safest protection, and additional sprays may not be required. “It is a personal choice to use these sprays as an aid when traveling or when you need to remove the mask, such as exercising and eating, but it may be too much, such as allergies to ingredients, not wearing masks properly, and lax epidemic prevention measures.”

He reminded that it is necessary to understand the local epidemic risk when traveling abroad, and it is best to wear a mask in crowded places and on public transportation.

The US FDA issued a warning letter to some companies that sell products that claim to prevent, treat, alleviate, diagnose or cure the new crown disease, saying that it may lead to a false sense of security and false impressions in the public, thinking that there is no need to strictly observe social distance and good hygiene habit etc.

Liang Zichao finally reminded that the function of nasal spray is different from that of masks.

“Masks not only provide personal protection,

There is also a source control function,

If everyone wears a mask,

Even though the mask is only 80% protective,

It can also reduce the overall risk of infection by 96%. “

He believes that depending on whether the new crown virus and other respiratory infectious diseases will become widespread after winter, it is more appropriate to consider relaxing the mask order this spring.

The technology is still immature and it is not recommended to buy in foreign countries

Nasal spray products are still under study, and the technology is still immature.

At this stage, you should not rely on this type of product for epidemic prevention purposes; as for using it as an auxiliary tool when eating, playing ball, or removing the cover of a wind instrument, you want to “be safe” and spray it. The most important thing is that there is no discomfort after use (do no harm).

Family doctor Lin Yonghe appeals to everyone to pay attention to:

◆ Pay attention to whether there is comprehensive scientific evidence and clinical research support.

◆Whether the research involves the sponsor’s conflict of interest. If there is funding from a pharmaceutical company, more care should be taken when analyzing the research results.

◆Whether the number of participants in the study (sample size) is sufficient.

◆Whether the Center for Health Protection approves or recommends the use of relevant products for the prevention of COVID-19, members of the public can visit the Center for Health Protection or the United Anti-epidemic website.

◆It is not recommended to buy anti-virus products in other places, because consumers may not understand the product labels, nor can they know whether the products are supported by research, whether the content is credible, etc.

Article Li Chuer “Ming Pao”

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