Tuesday, September 7, 2021

A Fresh Air Look at Ventilation

Environmental factors contribute to the spread of microorganisms causing diseases. Sunlight can kill viruses in minutes, while increased air pollution could be one of the risk factors of more severe outcomes. Humidity is also thought to be important. A team of scientists from Northeast US analyzed COVID-19 cases from 2669 counties and found that cold and dry weather and low levels of ultraviolet radiation are moderately associated with increased SARS-CoV-2 transmissibility, with humidity playing the largest role. 17.5% of the virus’ reproductive number was attributable to meteorological factors, with temperature accounted for 3.73%, humidity accounted for 9.35%, and UV radiation for 4.44%. This is in line with earlier findings about SARS-CoV-2 being less stable at higher humidity and warmer temperatures in human nasal mucus and sputum. Like in previous environmental studies, however, these fractions were not the same everywhere and were higher in northern counties. 

20 years ago, American scientists Wells and Riley developed a model of the airborne transmission of infectious diseases such as tuberculosis and measles. A novel modified version of this model was used to estimate the impact of relative humidity on the removal of respiratory droplets containing infectious virus particles. The results showed that this impact depended on the ventilation rate and the size range of virus-laden droplets.  It was concluded that increasing the ventilation rate is more beneficial, while installing and running humidifiers may not be an efficient solution to reduce the risk of COVID-19 disease in indoor spaces. 

A popular metric for airflow is Air Changes per Hour (ACH, also called Air Change Rate).  It tells how many times the air within a space can be replaced with fresh air each hour. Increasing the ventilation rate from 0.5 ACH to 6 ACH was predicted to decrease the infection risk by half. Studies of US houses and apartments found typical ACH values between 0.5 and 2.0 (with open windows). 4.0 ACH is the minimum air exchange rate acceptable for commercial buildings, but 1.5 ACH is the reality for most schools. Opening a car window raises ACH to 6.  Natural ventilation combined with novel technologies could help to increase fresh air intake with minimal energy cost.

Virus clouds can, indeed, be dispersed with some fresh, clean air. But fresh air isn’t going to stop the spread of microorganisms in high-density crowds. Effective ventilation is only one of basic infection control strategies along with hand/environmental hygiene, social distancing, case surveillance and other evidence-based measures. 


Aganovic A, Bi Y, Cao G, Drangsholt F, Kurnitski J, Wargocki P. Estimating the impact of indoor relative humidity on SARS-CoV-2 airborne transmission risk using a new modification of the Wells-Riley model. Building and environment. 2021 Aug 23:108278.

Ma Y, Pei S, Shaman J, Dubrow R, Chen K. Role of meteorological factors in the transmission of SARS-CoV-2 in the United States. Nature Communications. 2021 Jun 14;12(1):1-9.

Saturday, March 20, 2021

Anaphylaxis to COVID-19 vaccinies

Anaphylaxis  - severe, potentially life-threatening allergic reaction - can occur within seconds or minutes of exposure to allergens. Multiple cases of anaphylaxis have been described for COVID-19 vaccines. 

For the Pfizer/BioNTech vaccine, twenty-one anaphylaxis cases (a rate of 11.1 per million doses administered, later updated as 4.7/million from 28-million-datapoints), were documented in the US after receipt of the first dose of Pfizer-BioNTech COVID-19 vaccine during December 14–23, 2020. 17 of those had a documented history of allergies or allergic reactions, seven of whom had a history of anaphylaxis. 71% of them occurred within 15 min following the first dose of BioNTech vaccine. 

Anaphylactic shock to Pfizer vaccine happened in those with history of anaphylaxis to other vaccines (rabies and influenza A(H1N1) vaccine), drugs (prochlorperazine, antibiotics, sulfa drugs), venom (jellyfish sting) or nuts. Out of 21, 4 were allergic to sulfa drugs, 2 were allergic to nuts.

Moderna COVID-19 vaccine caused much fewer anaphylactic episodes (2.5 anaphylaxis cases per million doses administered for 27 million datapoints), but there were similarities with Pfizer cases. Out of 10 cases described in MMWR, 4 had Penicillin allergy (like 1 Pfizer case). Also in common were allergies to sulfa drugs and azithromycin.   

Turner et al, 2021The Pfizer-BioNTech vaccine contains lipid nanoparticles one of which is “pegylated” (Polyethylene glycol, molecular weight 2000 Da, abbreviated to PEG2000). The Moderna mRNA vaccine also includes a different pegylated lipid (also a PEG2000). Polyethylene glycols, also known as macrogols, could be causing serious allergic reactions ins some people.

One of the culprits of anaphylaxis in Astrazeneca could be polysorbate 80, used in the formulation of protein-based biopharmaceuticals, cosmetics, skin-care products, chewing gum and foods (ice creams and puddings). 41 reports of possible anaphylaxis were seen among around 5 million vaccinations in the United Kingdom. Four cases of people potentially experiencing anaphylactic reactions within 30 minutes of receiving the AstraZeneca vaccine have been reported in Queensland and one case with fatal outcome happened in Georgia. 

Polysorbate 80 is also an ingredient in Johnson and Johnson vaccine. For this vaccine, no cases of anaphylaxis were reported in ~22,000 participants of phase 3 clinical trial who received it. Five patients reported developing hives within a week. There was one case of what was considered severe “a hypersensitivity reaction,” but it was reportedly not related to anaphylaxis. Last month, however, one individual in South Africa developed anaphylaxis. No details have been published yet. 

According to the CDC, polysorbate 80 is an inactive ingredient in many viral vector vaccines for influenza (Fluarid, Fluax, etc), rotavirus, shingles, Hepatitis A, Hepatitis B, HPV, and meningococcus. Polysorbate 80 is also an ingredient in COVID-19 Sputnik V vaccine from Gamaleya Research Institute.


Turner PJ, Ansotegui IJ, Campbell DE, Cardona V, Ebisawa M, Yehia EG, Fineman S, Geller M, Gonzalez-Estrada A, Greenberger PA, Leung AS. COVID-19 vaccine-associated anaphylaxis: A statement of the World Allergy Organization Anaphylaxis Committee. World Allergy Organization Journal. 2021 Feb 3:100517.

Allergic Reactions Including Anaphylaxis After Receipt of the First Dose of Pfizer-BioNTech COVID-19 Vaccine — United States, December 14–23, 2020. MMWR Morb Mortal Wkly Rep 2021;70:46–51. DOI: http://dx.doi.org/10.15585/mmwr.mm7002e1external icon.

CDC COVID-19 Response Team; Food and Drug Administration. Allergic Reactions Including Anaphylaxis After Receipt of the First Dose of Moderna COVID-19 Vaccine - United States, December 21, 2020-January 10, 2021. MMWR Morb Mortal Wkly Rep. 2021 Jan 29;70(4):125-129. doi: 10.15585/mmwr.mm7004e1. PMID: 33507892; PMCID: PMC7842812.

Kounis NG, Koniari I, de Gregorio C, Velissaris D, Petalas K, Brinia A, Assimakopoulos SF, Gogos C, Kouni SN, Kounis GN, Calogiuri G. Allergic Reactions to Current Available COVID-19 Vaccinations: Pathophysiology, Causality, and Therapeutic Considerations. Vaccines. 2021 Mar;9(3):221.

Public Health England. COVID-19: the green book, chapter 14a.

Moghimi SM. Allergic Reactions and Anaphylaxis to LNP-Based COVID-19 Vaccines. Molecular Therapy. 2021 Mar 3;29(3):898-900.

Saturday, February 20, 2021

The eating environment

Our eating environment (for example, shape and color of dinner plate, people around us, size of the food package) determines food consumption which in its turn plays a crucial role in health management. 

Technology, in particular wearables and mobile phones, may help to improve the assessment of the eating environment, the food we eat, and efficacy of dietary interventions. 

What technologies are gaining steam in this field? 

Paper-based records, web or mobile food diaries and built-in barcode scanner have enjoyed some lime light but never really picked up.

Photograph-based diaries have evolved from Amazon's Mechanical Turk based services to Ecological Momentary Assessment apps using Deep Convolutional Neural Networks and nudging chatbots. When will this technology becomes ubiquitous? Or will it be completely automatic, done for us by passive sensing tools such as wrist-based eating detectors or our walls and places we order food from? As in an Australian hospital that offered a food ordering app (electronic food service, EFS) that would also do nutritional analysis. The patients seemed to really like it. Was it because there was not much else to do in the hospital? 

Food coaching apps will only keep evolving.


Sun J, Radecka K, Zilic Z. FoodTracker: A Real-time Food Detection Mobile Application by Deep Convolutional Neural Networks. arXiv preprint arXiv:1909.05994. 2019 Sep 13.

Jiang L, Qiu B, Liu X, Huang C, Lin K. DeepFood: Food image analysis and dietary assessment via deep model. IEEE Access. 2020 Feb 13;8:47477-89.

Roberts S, Chaboyer W, Hopper Z, Marshall AP. Using Technology to Promote Patient Engagement in Nutrition Care: A Feasibility Study. Nutrients. 2021 Feb;13(2):314.

Goldstein SP, Hoover A, Evans EW, Thomas JG. Combining ecological momentary assessment, wrist-based eating detection, and dietary assessment to characterize dietary lapse: A multi-method study protocol. Digital Health. 2021 Feb;7:2055207620988212.

Thursday, December 31, 2020

Warmth and Competence

Holidays are good for your health - if they warm your heart and your home. 

Exactly one year ago, on Dec. 31 2020, China first alerted the WHO of "viral pneumonia". Next day authorities shut the infamous wet market in Wuhan, and the rest is history. 

Today many will enjoy parental warmth remotely. Those least lucky will do it only in their hearts, remembering the good times. We have a lot to be grateful for to our parents. Beautiful childhood memories is one of those things.  

Scientific research shows that childhood parental warmth improves health, reducing the risk of having a cardiovascular problem and mortality by age 63. via our resting heart rate.  High-frequency heart rate variability (HFHRV), measured during the longitudinal study of over 1K US participants titled “Midlife in the United States”, significantly correlated with parenting scores such that warmer parenting predicted higher HF-HRV. This measure relates to the strength of Autonomic Nervous System and cardiovascular health. 

Another large study (over 1K young individuals in China), part of an even larger project that included extensive measures of executive function, decision making, memory, personality, and wellbeing, explored the whole genome to identify genetics mediating the effect of parental warmth on professional competence. Thee genes responsible were components of electrical circuitry in the human brain fine tuned by parental warmth to improve our ability to make decisions. 

But enough of science and the art. Let today be a new beginning.

Be happy, be warm, be successful. 


Alen NV, Sloan RP, Seeman TE, Hostinar CE. Childhood parental warmth and heart rate variability in midlife: Implications for health. Personal Relationships. 2020 Sep;27(3):506-25.

Chen C, Chen C, Xue G, Dong Q, Zhao L, Zhang S. Parental warmth interacts with several genes to affect executive function components: a genome-wide environment interaction study. BMC genetics. 2020 Dec;21(1):1-1.

Monday, April 13, 2020

Genes and Proteins of COVID-19

A pneumonia of unknown cause detected in Wuhan, China was first reported to the WHO Country Office in China on 31 December 2019.  The outbreak was declared a Public Health Emergency of International Concern on 30 January 2020 and declared a pandemic on March 11. By that time the disease was known as COVID-19 and the name of the new virus was SARS-CoV-2

Scientists worked at speed to make this virus's gene and protein information available at record time. 


Saturday, December 21, 2019

Flu Season 2019-2020

Influenza viruses are negative-sense single stranded RNA viruses of the Orthomyxoviridae family. There are four types of influenza viruses: A, B, C and D . In electron microscopy these types, especially A and B,  could be virtually indistinguishable. D is more similar to C.
Most of these viruses look like small spheres with spikes, although some could be irregularly shaped. Spikes are proteins and they are what's different in different forms of influenza. Typically, influenza A starts the early wave of the flu, and influenza B starts to show up at the tail-end of the season, in early spring. This year is't flu B that started the first wave while flu A may be responsible for the second wave. Is the flu shot working? It's still too early to predict.

Wednesday, August 28, 2019

Saving the Pond

Reproduced from Aurametrix

There are several million ponds in United States (Renwick et al, 2006), and many are in need for preservation. This pond (35°33'51.7"N 84°13'38.5"W), part of Kahite hiking trail system in East Tennessee, attracts a variety of wildlife, with ecological benefits and habitat. It preserves community open space and property values.

The pond began to deteriorate as invasive submerged plants such as Hydrilla (notoriously difficult to eradicate without serious chemical herbicides) started growing under the surface of the water causing problems for aquatic life. The pond used to be naturally cleaned by a stream connecting to Tellico lake, but the stream got clogged up and the pond is in need of help.

Dying Pond

Members of the community desire to save it because of its mystique, beauty and recreational value, and they need an economical and environmentally friendly way of restoring new life to our pond. This project would be a great example of civic engagement, helping to educate future Nature Conservancy volunteers. Here is the story of the pond.

Aerial view of the pond
It is not known when this small (surface area ~0.5 acres), tranquil pond was born in the scenic greenery of East Tennessee. The land area around the pond was owned by an Overhill Cherokee descendant, Bowhunter, sun of a local chieftain. For Cherokees, water was the source of all existence and the deposit of all living things. It marked both the beginning and the terminus of material life and persisted beyond the realm of the temporal into infinite existence. Going to water was a part of the ritual for obtaining long life and recovering from a thickness (Mooney, 2012). No doubt, Bowhunter would cherish and maintain his pond.
Beautifully maintained historic road

Shortly after the 1819 Calhoun treaty that established Monroe county, an early settler John McGhee purchased the land. Over the years the property was owned by Peter Moser, Shakely Farma, Bob Starnea, Jogn Caraon and other families. In 1920s, the first documented house within the boundaries of modern Kahite neighborhood was built by Bert Anderson. The settlement along Mt. Zion Road within the boundaries of Kahite began with a tenant house built by the Robinsons.  In the late 1940s, the land was acquired by the Williams family who built a house and a barn near the pond. They used the pond for agricultural purposes, as water sources for livestock.

In the 1960s the Tennessee Valley Authority began buying up the land  for the creation of Tellico Reservoir. And so water spread over the valley and the lake was born. But a part of Mt. Zion road used by the early settlers was still there and so was the pond.

The Pond after the rain
In the 1960s Monroe county lagged badly behind the rest of the state in most important economic measures. Development of Kahite, the final major neighborhood of Tellico Village, started in August 1996 with the goal to bring jobs and economic growth. But there was more to it, as members of the community volunteered to plant community gardens, build trails and were eager to turn the land into a welcoming haven for humans and wildlife.

Pond in need of restoration
The shoreline lands around Tellico lake are no longer stagnant communities, but a recreation wonderland maintained by environment and wildlife conservation enthusiasts. It's a land of educated volunteers willing to employ new sustainable green chemistry approaches and innovative methods of building and maintaining healthy ecosystems.

Ponds provide enjoyment from offering a closeness to nature and increase the habitat available for our freshwater wildlife.

We do not inherit our ponds from previous generations, we borrow them from the future ones. We need to maintain them for their beauty, for their cultural significance, and protect next generations of human beings and other inhabitants of the Earth.


Renwick WH, Sleezer RO, Buddemeier RW, Smith SV. Small artificial ponds in the United States: impacts on sedimentation and carbon budget. In Proceedings of the Eighth Federal Interagency Sedimentation Conference 2006 Apr 2 (No. 8th, pp. 738-44).

Gary Mulliner, 2010, History of Kahite, Iterpretive Exhibit.

Mooney J. Myths of the Cherokee. Courier Corporation; 2012 Mar 7.

Stager JC, Wiltse B, Hubeny JB, Yankowsky E, Nardelli D, Primack R. Climate variability and cultural eutrophication at Walden Pond (Massachusetts, USA) during the last 1800 years. PloS one. 2018 Apr 4;13(4):e0191755.

Genoa R. Warner, Yogesh Somasundar, Kyle C. Jansen, Evan Z. Kaaret, Cindy Weng, Abigail E. Burton, Matthew R. Mills, Longzhu Q. Shen, Alexander D. Ryabov, Gabrielle Pros, Tomislav Pintauer, Saborni Biswas, Michael P. Hendrich, Julia A. Taylor, Frederick S. Vom Saal, Terrence J. Collins. Bioinspired, Multidisciplinary, Iterative Catalyst Design Creates the Highest Performance Peroxidase Mimics and the Field of Sustainable Ultradilute Oxidation Catalysis (SUDOC). ACS Catalysis, 2019; 7023 DOI: 10.1021/acscatal.9b01409