Qs people asked me on science and my replies to them - Part 181

Q: Can we handle and have food immediately after using hand sanitizer? 

Krishna: You should wash your hand if you use hand sanitizers before eating food. You must wash your hands immediately after using hand sanitizer, and before handling food—it will not diminish the virus deactivation effects.  It's vital because washing your hands removes chemicals and other fragrances that exist in commercially produced hand sanitizers that could make you and your family sick. The exception is situations where food products are not handled by hand, such as when products are sealed.

Q: Can bugs develop resistance to hand sanitizers too? 

Krishna: Although the overuse of antibiotics creates resistance, if a hand sanitizer is alcohol-based, it does not create 'superbugs' or exacerbate the spread of antibiotic-resistant bacteria. The reason why alcohol is so vital in hand sanitizer is that it kills germs in seconds by destroying the cell membrane and bacterial proteins. Because of how rapid it is, there is no system where germs can become resistant to hand sanitizer.

Heavy use of other chemical based sanitisers could boost antimicrobial resistance.

Q: Washing hands with soap and water or using hand sanitizers: which option is better?

Krishna: If you ask experts, they would say washing hands with soap and water is the better option. Hand sanitizer kills the germs but does not remove them from your hands. The action of physically washing your hands properly is what removes the germs physically and down the drain."   But in instances where you don't have access to water and soap, sanitizer serves as a good alternative, but it won't beat an old fashioned hand-wash.

Another reason hand-washing is more effective is because mucus (coming out of the mouth  from sneezing, coughing, or blowing your nose) encases viruses and forms a protective barrier against ethanol and therefore cannot be deactivated by hand sanitizer until the mucus is completely dry, according to a scientific study (4). The study found that washing hands, even just with water, was proven to deactivate the influenza A virus within 30 seconds while mucus was still wet. But the act of using soap is still important: Soap contains fat-like substances called amphiphiles, similar to the lipid membrane that surrounds a virus, so when you wash your hands, the fat from the soap binds with the virus' membrane causing it to disconnect from the virus, making it essentially fall apart. 

So if you want to effectively clean your hands, you should wash them thoroughly for 20 seconds or more in warm (or cold) water with soap, being sure to get in-between your fingers, on the backs of your hands, and underneath fingernails. The type of soap is not essential, either: Antibacterial soap isn't necessary for preventing COVID-19 as it's a virus (not bacteria). That is according to WHO.

But ... a virologist recently said, that is based on speculation and not tested actually. read ehre what eh says about this: https://kkartlab.in/group/some-science/forum/topics/contradictory-r...

Q: Can sanitizers cause harm?

Krishna: Yes! Your hands feel drier and rougher after routinely using sanitizers. This is because of the high alcohol content (an effective sanitizer should have at least 60%-65% ethyl alcohol), which can actually be damaging to your skin. There have been studies in the past about how hand sanitizers may disrupt your healthy microbiome and actually leave you more vulnerable to some kind of infections. And by breaking down the skin, leaving it cracked and chapped, germs can enter these crevices, making sanitizing more of an issue than a reactive measure.

So you have to apply moisturisers to counter these things.

Aside from the high alcohol content, added ingredients may cause harm to the skin. Moreover, if you apply too much of sanitizers, your skin might actually absorb the alcohol and it might show up in your body! Research has found alcohol in the bloodstream of people who used hand sanitizers in excess. Alcohol from the sanitizers can also be absorbed through inhaling its vapours.

Q: What are other chemicals used in sanitizers? 

Krishna: Popular non-alcohol alternatives like benzalkonium chloride are  also used. 

According to some (5) Hypochlorites

too are used in a few sanitizers. Effectiveness, low cost and ease of manufacturing make hypochlorites the most widely used sanitizers. Sodium hypochlorite is the most common compound and is an ideal sanitizer, as it is a strong oxidizer. These compounds inhibit cellular enzymes and destroy DNA. Spores, however, are resistant to hypochlorites, as the spore coat is not susceptible to oxidation except at high concentrations coupled with long contact times at elevated temperatures. Disadvantages of hypochlorites are corrosiveness to metals, health concerns related to skin irritation and mucous membrane damage and environmental contamination. The latter is of concern as chlorine can combine with organic substances to form toxic chlorinated compounds, such as trihalomethanes and dioxins. 

Hypochlorites cause broad microbial mortality by damaging the outer membrane

Another one is Chlorine Dioxide
This inorganic compound is a broad sanitizer effective against bacteria, fungi and viruses. Chlorine dioxide is an oxidizer that reacts with the proteins and fatty acids within the cell membrane, resulting in loss of permeability control and disruption of protein synthesis. Chlorine dioxide reacts more selectively with compounds present in microbial cells as opposed to reacting with organic compounds in general. This ability allows chlorine dioxide to function in more organically loaded solutions, though as organic load increases, efficacy does decrease. Chlorine dioxide functions well over a pH range of about 6 to 10, thus allowing increased mortality of some microbes at higher values. Another advantage is that chlorine dioxide does not form chlorinated organic compounds, making it more environmentally friendly.

Iodophors
These compounds are less active than hypochlorites but are effective sanitizers and disinfectants. Iodophors attach to the sulfurs of proteins such as cysteine, causing inactivation and cell wall damage. Carriers with iodophor solutions allow a sustained-release effect, resulting in continuous microbial mortality. Iodophors fare better in situations in which the pH is slightly acidic, as less active forms exist above neutral pH. 
Peroxyacetic Acid (PAA)
PAA is an effective sanitizer that is active against many microorganisms and their spores. Mortality is produced by the disruption of chemical bonds within the cell membrane. PAA-based sanitizers are frequently paired with stabilized hydrogen peroxide. These sanitizers function well under cold conditions (~ 4 °C), thus producing acceptable microbial mortality on equipment normally held below ambient temperature. PAA is also effective in removing biofilms and is more active than hypochlorites.

Quaternary Ammonium Compounds (QACs or Quats)
Quaternary ammonium compounds are fairly complex chemicals in which nitrogen is bound to four organic groups. The positively charged cations in the compounds bind with the acidic phospholipids in the microbial cell wall.

However, except for alcohol based sanitizers, all the other chemical based sanitizers can make bacteria resistant to them. So it is not wise to use them.

Q: Can BCG vaccination prevent corona virus infection?

Krishna: There is no real evidence to show that it does.

But USA scientists say that the BCG or the Bacillus Calmette-Guerin vaccine, given to millions of Indian children after birth to protect them against tuberculosis, could be a "game-changer" in the battle against the deadly Corona virus (1).

According to WHO(2), there is no evidence that the Bacille Calmette-Guérin vaccine (BCG) protects people against infection with COVID-19 virus. Two clinical trials addressing this question are still underway. In the absence of evidence, WHO does not recommend BCG vaccination for the prevention of COVID-19. However, WHO continues to recommend neonatal BCG vaccination in countries or settings with a high incidence of tuberculosis.

There is experimental evidence from both animal and human studies that the BCG vaccine has non-specific effects on the immune system. These effects have not been well characterized and their clinical relevance is unknown.

On 11 April 2020, WHO updated its ongoing evidence review of the major scientific databases and clinical trial repositories, using English, French and Chinese search terms for COVID-19, coronavirus, SARS-CoV-2 and BCG.

The review yielded three preprints (manuscripts posted online before peer-review), in which the authors compared the incidence of COVID-19 cases in countries where the BCG vaccine is used with countries where it is not used and observed that countries that routinely used the vaccine in neonates had less reported cases of COVID-19 to date. Such ecological studies are prone to significant bias from many confounders, including differences in national demographics and disease burden, testing rates for COVID-19 virus infections, and the stage of the pandemic in each country. 

Q; Can vitamin C help prevent corona virus infection?

Krishna: Most of the test results are still in the pre-print stage. So we can't give a definite answer. 

According to reports from some hospitals,  one of the symptoms/effects of COVID in some patients is sepsis. This is often accompanied by lowered vitamin C levels in the body. So the treatment isn’t actually directly treating COVID, it’s attempting to prevent sepsis caused by COVID in some patients.

ZhiYong Peng, MD of the Department of Critical Care Medicine at Zhongnan Hospital of Wuhan University recently registered a phase 2 clinical trial on ClinicalTrials.gov to test the efficacy of vitamin C infusions for the treatment of severe acute respiratory infection (SARI) associated with the novel coronavirus. The study description notes that vitamin C is an antioxidant that may help prevent cytokine-induced damage to the lungs.

 However not all experts agree. Some say,  "Your immune system does need vitamin C to work right. But extra won't help you avoid a cold. It may make it go away faster or not feel as bad – if you were taking it before you got sick.

Currently, there are no effective targeted antiviral medications for COVID-19. There are no preventive drugs too. The main treatment consists of supportive therapy to manage symptoms.

Q: How long should we endure these quarantine, self isolation, containment etc.? Till we find a vaccine or drugs - even if they take a year or two?

Krishna. Had people co-operated fully, we would have controlled Covid 19 to a large extent by now. 

The key goal of these measures  is to slow down the case rate to the point where medical facilities can handle it, so flattening the curve is very vital to have things under control. In addition to lessening the number of cases, this strategy buys us time to get us prepared.

Anyway, we know we can't sustain these preventive measures for long. We have to use our imagination to still keep the situation under control, till a solution is identified.

Q: Why are some people who are positive for COVID 19 are testing negative?

Krishna: Experts think this might be due to errors in testing in most cases. 

However, we are also getting reports that  coronavirus patients who initially tested negative tested positive for the virus days later. South Korea reported that 91 coronavirus patients they believed to have recovered from the disease tested positive for the virus again.

Guidelines from WHO on clinical management recommended that a clinically recovered COVID-19 patient should test negative for the virus twice, with tests conducted at least 24 hours apart, before being discharged from the hospital.

The COVID-19 patients in South Korea were being considered for discharge after testing negative for the disease - however, tests administered later showed positive results. South Korean health officials said they would be launching epidemiological investigations to determine what was behind the trend.

Jeong Eun-kyeong, the director of the Korea Centers for Disease Control and Prevention, said in a news briefing that the virus may have "reactivated" in the patients, as opposed to the patients being re-infected again. "While we are putting more weight on reactivation as the possible cause, we are conducting a comprehensive study on this," Jeong said just yesterday.

There have been many cases when a patient during treatment will test negative one day and positive another.

The number of patients who were believed to have been cleared of the coronavirus but later tested positive jumped from 51 on Monday to 91 on Friday. Shortly after, WHO announced it would also be looking into the recent COVID-19 trend in South Korea as well. 

According to WHO, current studies show that patients with mild COVID-19 experience a period of about two weeks between the onset of symptoms and clinical recovery. But it remains unclear why these patients are testing positive after they were believed to have recovered from COVID-19.

"As COVID-19 is a new disease, we need more epidemiological data to draw any conclusions," the WHO statement added.

So, we don't have any clear cut understanding yet on this new Corona virus infection, as the studies are still going on. 

Q: Why do we hate some sounds and get angry when we hear them?

Krishna: Misophonia! heard about it?
The sound of people chewing, slurping, tapping, or humming can drive some people into a rage, and scientists have actually discovered the neurological wiring responsible for this strange condition. It describes the unreasonable emotions that well up in some of us when we hear certain repetitive noises being produced by other humans. People with this condition experience annoyance or even anger at the clacking of a keyboard, the rustling of a chip packet, or the smacking of lips. It is a health condition (3)!

A study published in the Journal of Clinical Psychology in 2014 suggested that misophonia could affect as much as 20 percent of the population. In 2017, a team led by researchers from Newcastle University in the UK found evidence of changes to the brain's frontal lobe that could account for the emotional response triggered by sounds in those with misophonia. In people with misophonia, the triggering noises correlate with increased activity in various regions of the brain, including the frontal lobe and the anterior insular cortex (AIC). The AIC is buried deep in the fold separating the frontal lobe and parietal lobe from the temporal lobe of the brain. It's responsible for a bunch of mediation tasks, including managing emotional experience. It also plays a role in integrating signals from the outside world with information inside the body.

Those with misophonia not only had increased AIC and frontal lobe activity, but also in the ventromedial prefrontal cortex (vmPFC), hippocampus, and amygdala. Measurements taken of the structure of the vmPFC indicated they had thicker insulating myelin sheaths, which helps nerves carry messages.

Taken together, the evidence suggests that those with misophonia have brains that struggle to control the spread of messages associated with certain sounds.

You can find a recent research paper on this here: https://www.cell.com/current-biology/fulltext/S0960-9822(16)31530-5

Q: Does hand washing remove all the germs from hands?

Krishna: Wash your hands with a good soap and water for atleast 30 seconds. Then, this is very important, dry them completely with paper towels or tissues and then use the same tissues to turn-off taps, handling door knobs etc and then throw them into thrash cans. 

This is the better way to deal with germs. 

Footnotes: 

1. https://timesofindia.indiatimes.com/life-style/health-fitness/healt...

2. https://www.who.int/news-room/commentaries/detail/bacille-calmette-...

3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4547634/

4. https://www.cidrap.umn.edu/news-perspective/2019/09/hand-sanitizer-...

5. https://www.foodsafetymagazine.com/magazine-archive1/augustseptembe...