Is the "light vaccine" used by the Chinese Olympic delegation the ultimate weapon against the new coronavirus?

Koko, have you heard of "light vaccine"?

Hmm, I haven’t heard of it. Have the experts developed a new vaccine?

I’m not sure. I heard it’s a black technology used by Olympic athletes.

That's awesome! Can I use it?

Too long to read version:

"Light vaccine" is not a new vaccine, nor is it a medicine.

"Photovaccine" is a UV disinfection device, which can be considered as an UV lamp.

Ultraviolet rays can kill viruses, bacteria, and fungi at the right dosage.

When using ultraviolet light sources, great care should be taken to avoid direct exposure to human skin, mucous membranes and eyes.

What is a “light vaccine”?

Recently, an article titled "Secret Weapon "Light Vaccine" Ensures Zero COVID-19 Infection for the Chinese Olympic Delegation!" went viral on WeChat Moments.

The so-called "light vaccine" refers to an advanced ultraviolet disinfection equipment that can achieve 99.99% sterilization rate against microorganisms such as viruses and bacteria, especially the new coronavirus.

Lumenizer 300, a brand of 222 nanometer optical disinfection equipment

Image source: https://mp.weixin.qq.com/s/9rMT-HQEpC0IN34t-lucyA

This disinfection equipment can be understood as a lamp that emits ultraviolet light. It uses a krypton chloride excimer lamp as the light source and filters out 222nm ultraviolet wavelengths through a special filter structure. 222nm wavelength ultraviolet light can destroy the DNA or RNA molecular structure in bacteria, spores and viruses, making the pathogens inactive and unable to regenerate. This is its disinfection principle.

In fact, "light vaccine" has nothing to do with "vaccine". First of all, the use of this disinfection equipment will not cause the human body to produce any antibodies. Secondly, "light vaccine" does not necessarily have any effect on the human body. The manufacturer of this disinfection equipment has also stated that the term "light vaccine" is not scientific and rigorous enough.

Ultraviolet light is a commonly used sterilization method. Its killing effect on microorganisms comes from two aspects. On the one hand, it is the effect of ultraviolet light itself, and on the other hand, it is the effect of ozone produced by ultraviolet light.

Disinfection of college entrance examination papers of candidates in Guangzhou isolation ward

Image source: Beijing News

First of all, ultraviolet radiation refers to electromagnetic radiation with a wavelength of 100nm-400nm, which can be divided into the following three bands:

Long-wave ultraviolet rays: wavelength is 315nm-400nm, UVA; medium-wave ultraviolet rays: wavelength is 280nm-315nm, UVB; short-wave ultraviolet rays: wavelength is 100nm-280nm, UVC.

Image source: Guo Xiaohong

The shorter the wavelength, the stronger the energy of ultraviolet radiation, and the stronger its ability to cause photobiological effects.

The essence of ultraviolet sterilization is a photochemical reaction process. The research of Ren Zhuo Chen et al. shows that the response of microorganisms to ultraviolet radiation is highly correlated with the response of nucleic acids to ultraviolet radiation, which indicates that ultraviolet radiation has a bactericidal effect mainly by affecting nucleic acids. The research of Christine A. Huselton et al. shows that the absorption of ultraviolet radiation by nucleic acids has a high value in the 200nm-250nm band, which means that the UVC band is the most bactericidal part of ultraviolet radiation. Among them, the band near 260nm has been confirmed to be the ultraviolet with the highest bactericidal efficiency. Its effect can cause photochemical damage to the DNA tissue in various bacteria, viruses, fungi and other pathogens, causing the cells to die due to the loss of replication ability.

In addition to its own bactericidal effect, the vacuum ultraviolet band can promote the production of ozone, which also has a bactericidal effect. A large number of studies have shown that the bactericidal effect of the combination of ultraviolet and ozone is better than that of ozone alone.

UV rays are also harmful

It is true that ultraviolet rays have a bactericidal effect, but we should not subconsciously ignore that the human body is also made up of cells one by one. Excessive ultraviolet rays will also have an impact on the human body.

Ultraviolet rays have an impact on both the skin and eyes. When the skin is exposed to ultraviolet rays, red spots, dark spots or pigmentation are prone to occur. The cornea, conjunctiva and lens are sensitive to ultraviolet rays. Exposure to ultraviolet rays can cause visual fatigue and eye pain, and in severe cases can cause cataracts.

Application requirements of UV sterilization

The equipment that can be generally used for sterilization and disinfection with ultraviolet rays includes ultraviolet fluorescent lamps and ultraviolet LEDs.

Ultraviolet disinfection lamp source: http://m.jia.com/zixun/jxwd/833015.html

However, there are two characteristics of ultraviolet rays that determine their application limitations:

Ultraviolet rays are easily blocked, so they can only sterilize the surface of objects, which means that they cannot sterilize deep locations;

As mentioned earlier, ultraviolet rays are harmful to the human body, so when using ultraviolet sterilization, the human body cannot appear in areas exposed to ultraviolet radiation.

Please rest assured that there is no need to be afraid of ultraviolet rays. The characteristics of ultraviolet rays that are easily blocked make it very simple to protect against ultraviolet rays. As long as you wear good clothes and goggles and do not expose your skin to ultraviolet radiation, there will be no impact.

What is different about 222nm?

The "light vaccine" does not use the traditional ultraviolet disinfection band, but instead uses a 222nm wavelength.

According to research by Professor DAVID J. BRENNER, Director of the Columbia University Center for Radiological Research:

The general medical ultraviolet wavelength is around 254nm, which can kill germs but is harmful to the human body;

222nm is harmless to the human body;

222nm can kill the new coronavirus.

One benefit brought by these two characteristics of 222nm is the so-called "human-machine coexistence", which is also the biggest promotional point of "optical vaccine".

The coexistence of humans and machines means that sterilization and disinfection can be carried out in real time in scenes where people are working, moving, or resting. This can achieve higher sterilization efficiency and better flexibility of use.

"Light vaccines" were flexibly arranged in the corridors of the Chinese team

Image source: Fudan University WeChat official account

Now a core question is, why is 222nm safe for humans?

Professor BRENNER's website states:

222 nm light is safe for us because it cannot even penetrate through the dead-cell layer on the surface of our skin or the tear layer on the surface of our eyes - but because bacteria and viruses are physically very small, 222 nm light does have enough penetration to efficiently kill them.

The general idea is that 222nm is a very appropriate wavelength. Ultraviolet rays of this wavelength can be blocked by the tear film and skin of the eyes without causing any harm to the human body, while at the same time being able to penetrate viruses and kill them.

How to use "light vaccine"

I think the question that everyone is more concerned about is whether the "light vaccine" is effective? When can we use the "light vaccine"? How to use the "light vaccine"?

As a type of UV sterilization equipment, the "light vaccine" is certainly not the first. There are many types of civilian UV sterilization equipment, and everyone has many choices.

But even the manufacturers of the "light vaccine" themselves emphasize that this product only provides an additional means of environmental disinfection and a safety barrier. The zero infection of the Chinese Olympic delegation is the result of strict compliance with various epidemic prevention regulations, and cannot rely solely on a certain technology or product. Although this product has played a certain role, vaccines, masks, disinfectants, social distance and other epidemic prevention products and means are irreplaceable.

In addition, the national standard GB 28235-2020 "Hygiene Requirements for External Disinfectors" stipulates that "ultraviolet disinfectors should be maintained by professionals, and protective glasses should be worn during disinfection operations under ultraviolet light. Protective clothing should be worn when necessary to avoid direct exposure to human skin, mucous membranes and eyes."

From this, we can draw the following conclusions:

There is no doubt that UV disinfection equipment has a clear disinfection effect;

When using UV disinfection equipment, you should take precautions. Even with new technology such as 222nm, it is never a wrong choice to avoid direct exposure to UV light.

There are many ultraviolet disinfection devices that can be purchased and used now, but for "light vaccines" that can "coexist with humans and machines", they may be available in the near future, or they may have to wait for a while. We might as well give scientific researchers more time to accumulate more experimental data;

Even with ultraviolet disinfection equipment, the epidemic prevention requirements must not be neglected at all, as epidemic prevention is a comprehensive project.

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The development of technology also requires a rigorous and realistic scientific spirit and solid and rich experimental data to better benefit mankind. I believe that with the joint efforts of all people, the development of many new technologies will surely help mankind achieve a great victory in the fight against the epidemic.

References

[1] Ren ZC, Craik SA, Bolton J R. Comparison of the action spectra and relative DNA absorbance spectra of microorganisms: Information important for the determination of germicidal fluence (UV dose) in an ultraviolet disinfection of water [J]. Water Research, 2009, 43(20):5087-5096.

[2] Huselton CA, Hill H Z. Melanin photosensitizes ultraviolet light (UVC) DNA damage in pigmented cells [J]. Environmental & Molecular Mutagenesis, 2010, 16(1):37-43.

[3] Zhang Yongji, Xue Guangbo. Application of ultraviolet disinfection technology and its verification technology [C]// National Disinfection and Disease Prevention Academic Conference and National Disinfection Industry Development Seminar. 2007.

[4] Xia Guanyingxuan, Lu Xiaoqing, Chen Yaoyao, et al. Experimental study on the bactericidal effect of LED ultraviolet lamp[J]. Chinese Journal of Disinfection, 2017, 34(1):1-2.

[5] Guo Weihong, Yuan Shidong, Yang Rui, Zhang Tao. Research and application of bactericidal characteristics of UVC LED[J]. Journal of Beijing Institute of Technology (Natural Science Edition), 2019, (S1): 102-107.

[6] Buonanno, M., Welch, D., Shuryak, I. et al. Far-UVC light (222 nm) efficiently and safely inactivates airborne human coronaviruses. Sci Rep 10, 10285 (2020).

[7] Welch, D., Buonanno, M., Grilj, V. et al. Far-UVC light: A new tool to control the spread of airborne-mediated microbial diseases. Sci Rep 8, 2752 (2018).

Author: Dr. Guo Weihong, Shanghai Institute of Technical Physics, Chinese Academy of Sciences Editor: Jiudayi — END —

The copyright of the online pictures belongs to the original author. The article belongs to Shanghai Science and Technology Museum.