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Welcome to the April newsletter. The goal of this newsletter is to provide information and analysis of timely topics from recent articles published in the medical literature. I hope you find this information useful and helpful in your health journey.
The COVID-19 disease caused by SARS-CoV-2 continues to dominate our lives. We are currently starting to transition from our "safer at home" status with some businesses reopening and hopefully more opening soon. There continues to be a lot of information and misinformation out there from the media and on social media. Most of us continue to be concerned about our risk for disease as well as our risk of financial disaster personally and as a country.
COVID-19 isn't going anywhere soon. We don't have a lot of definitive answers about this virus yet. This makes it difficult to project what the proper response is to take as an individual and for our society. The first article this month is a projection done by a group out of Harvard Medical School. I have been wary of a lot of projections as most have been wrong by several orders of magnitude. I included this one as it gives various projections based on the potential properties the virus may have, and based on this, provides some analysis that looks to be useful as we move forward with reopening society.
There are two main ways that the virus spreads. The main way is through direct contact with droplets from coughing or sneezing. The second way the virus potentially spreads is through self-inoculation where our contaminated hand makes contact with our face, especially our mouth and nose. The second study demonstrates that touching our face is a common habit but the frequency of touching will probably surprise you. I also offer some tips to break this habit.
There has been a lot of discussion and scrutiny of travel restrictions to fight the virus. The third study is an analysis of air travel and the effects that a simple change could have on the potential spread of an infectious disease. We can all make a difference in preventing the next pandemic.
If you are feeling sick, please call me first. We can discuss your symptoms and decide the best course of action for you, including testing. Please continue to wash your hands frequently, avoid touching your face, and avoid going out if you are sick.
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Looking Into the Crystal Ball...
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Projecting COVID-19 infection dynamics
It has become obvious that we really don't have any firm answers about the future of the SARS-CoV-2 (COVID-19) pandemic. We currently have no known effective therapeutic medications and no vaccine is forthcoming in the near future. We have been using public health measures of "shelter in home" and "social distancing" for prevention. At best, these techniques buy us time for advancement in treatment and development of therapeutics and a possible vaccine. As we try to figure out the best way for our society to move forward the only thing we can do is to try to look at educated and informed predictions of what may happen over the coming weeks and months. This projection is from a group out of the Departments of Epidemiology, Immunology and Infectious Diseases at Harvard Medical School. The group takes into account the possible contributions of seasonality, duration of immunity, and cross-protection imparted by prior infection with the two other betacoronaviruses in common circulation (HKU1 and OC43). Then, they provide a variety of scenarios that simultaneously assess the effects of the length and strength of social distancing.
- It is urgent to understand the future of severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) transmission. We used estimates of seasonality, immunity, and cross-immunity for betacoronaviruses OC43 and HKU1 from time series data from the USA to inform a model of SARS-CoV-2 transmission. We projected that recurrent wintertime outbreaks of SARS-CoV-2 will probably occur after the initial, most severe pandemic wave. Absent other interventions, a key metric for the success of social distancing is whether critical care capacities are exceeded. To avoid this, prolonged or intermittent social distancing may be necessary into 2022. Additional interventions, including expanded critical care capacity and an effective therapeutic, would improve the success of intermittent distancing and hasten the acquisition of herd immunity. Longitudinal serological studies are urgently needed to determine the extent and duration of immunity to SARS-CoV-2. Even in the event of apparent elimination, SARS-CoV-2 surveillance should be maintained since a resurgence in contagion could be possible as late as 2024.
What we know about seasonal coronaviruses (common cold viruses HKU1 and OC43):
- Second most frequent cause of the common cold
- May be asymptomatic or associated with mild to moderate upper respiratory illness
- They are seasonal - mainly late autumn through early spring with peaks typically in October and November
- Immunity wanes over the course of a year
- Some cross-protection exists between the viruses and SARS-CoV-1, this could extend to SARS-CoV-2
- Less infectious than SARS-CoV-2
What we know and don't know about SARS-CoV-2:
- Doesn't seem likely to be a single wave (like SARS-CoV-1) which is then controlled
- More likely to resemble a pandemic influenza with an initial global wave of infection followed by seasonal circulation
- Seasonal transmission is unknown, but it seems to be able to proliferate any time of year (may not be mainly seasonal)
- If there is some seasonality to it, we will have a large winter outbreak
- The high infectiousness near the start of often mild symptoms makes SARS-CoV-2 considerably harder to control with case-based interventions such as intensive testing, isolation and tracing, as compared to the SARS-CoV-1 and MERS coronaviruses
- If immunity is permanent or long-lasting it could disappear in a few years (like SARS-CoV-1)
- If immunity is not permanent, it will enter circulation as the 5th seasonal coronavirus with annual, biennial or sporadic patterns, depending on length of immunity
- If low levels of cross-protection from other coronaviruses exist, it might allow a resurgence of SARS-CoV-2 following a low activity period of a few years
Effects of social distancing
- Short duration of social distancing just displaces cases into the near future. It delays the peaks but we will still have high infection rates
- Longer durations of social distancing push cases back but will result in significant outbreaks in fall and winter and likely higher overall infection rate
- Permanent moderate to high social distancing keeps SARS-CoV-2 down, but would be unacceptable as as society
- Intermittent social distancing, based on surveillance, may help keep case loads in check until therapeutics or a vaccine is available.
There is no perfect choice. We have "flattened the curve". Social distancing was designed to slow the number of cases, but it will not reduce overall cases over time in the absence of treatments or vaccine. Now our leaders have to decide if we take the risk of more cases now and reopen in some fashion, or stay closed and likely push cases back to the fall and winter which may ultimately lead to a higher number of infected people. We know from experiences with other coronaviruses that depletion of susceptibles for each strain was negatively correlated with transmissibility of that strain. This is why coronaviruses peak early, then go down as the season goes on, there are fewer susceptibles as more people have "seen" the virus. We have reduced the epidemic peak size with the measures we have taken. There will be a resurgence and increase in cases as we start to reopen society. This simulation predicts resurgence peak size could be nearly the same as the peak size of an uncontrolled epidemic if our social distancing was so effective that virtually no population immunity was built.
A surge of SARS-CoV-2 will happen in the fall and if this continues deep into the winter at the same time as the normal surge in influenza (January-March) it will be much more likely to overwhelm our medical system and result in a higher number of deaths. Pushing cases back with prolonged social isolation seems likely to make the fall/winter surge of SARS-CoV-2 even worse as there will be a higher number of susceptible people, especially children, who generally will be asymptomatic but will spread the virus. Perhaps we will find an efficacious treatment by then, but this seems unlikely. There will not be a vaccine ready by this fall for the general public and even having one in 18 months seems unlikely at this point. We have improved our treatment of the critically ill with better medical management. We may need to institute regional intermittent social distancing for outbreaks moving forward. If serological data reveals the existence of many undocumented asymptomatic infections that lead to immunity (which seems to be happening), less social distancing may be required. Serology could also indicate whether cross-immunity exists between SARS-CoV-2, HCoV-OC43, and HCoV-HKU1, which could affect the post-pandemic transmission of SARS-CoV-2.
What does all this mean? COVID-19 isn't going away soon. Prolonged shelter at home and social distancing will make things worse this fall and winter and could make the '20-'21 influenza season a disaster and result in more deaths than no action at all. People need to interact so there become fewer susceptibles. This doesn't mean we should have 100,000 people at Summerfest next week. There will be an uptick in cases as businesses reopen. This is inevitable. We can move forward in a gradual progression, but taking weeks between progressions is probably too slow and will still cause the fall peak to be worse. Shooting for basic reproduction numbers of <1 is unrealistic. Closing summer camps, pools, and sports leagues for kids is not helpful. An argument could be made to send kids back to school for the last month now to avoid some of the fall spread which will inevitably occur from kids in school, especially if there is a bit of seasonality to the virus. Our serological testing over time will help us to know the length of immunity which will determine our policies moving forward. If it is long lasting it will burn out over several months up to a few years. If shorter, we will have periodic outbreaks. The fastest we have ever developed a vaccine for a new virus is 5 years (Ebola). There is no guarantee that we will develop a vaccine and if we do it will not be ready in the fall. Even 18 months is probably unrealistic to develop, test, run human studies and mass produce millions of doses (in addition to the normal influenza vaccines). There was work done on a SARS-CoV-1 vaccine so we could have a head start which could cut the timeline of the initial phases.
We are already seeing negative medical effects on our society of our current policies. People are not coming in with heart attacks and strokes. Appendixes are rupturing instead of being treated early. Cancers are not being diagnosed and treatments are being delayed. Emergency rooms are telling people not to come in. Depression is up. Suicides are up. Domestic abuse is up. There are lots of medical problems not getting appropriate treatment. This needs to stop now.
We have flattened the curve. It's time to stop the obsession with running tallies of cases and deaths. Stop berating each other on social media. We can't eliminate this virus in a few months and we may never eliminate it. Continue work on therapeutics as well as a vaccine. We didn't beat HIV with a vaccine. We beat it with therapeutics. Let's figure out how to live with it and move forward.
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Face touching is a frequent habit
Viruses can be spread through self-inoculation. This is transmission where a person's contaminated hand makes subsequent contact with other body sites (mainly mucus membranes) which results in the introduction of contaminated material into the body. This study of medical students looked at the frequency and length of face touching in a 60-minute period.
Abstract:
- Background: There is limited literature on the frequency of face-touching behavior as a potential vector for the self-inoculation and transmission of Staphylococcus aureus and other common respiratory infections.
- Methods: A behavioral observation study was undertaken involving medical students at the University of New South Wales. Their face-touching behavior was observed via videotape recording. Using standardized scoring sheets, the frequency of hand-to-face contacts with mucosal or nonmucosal areas was tallied and analyzed.
- Results: On average, each of the 26 observed students touched their face 23 times per hour. Of all face touches, 44% (1,024/2,346) involved contact with a mucous membrane, whereas 56% (1,322/2,346) of contacts involved nonmucosal areas. Of mucous membrane touches observed, 36% (372) involved the mouth, 31% (318) involved the nose, 27% (273) involved the eyes, and 6% (61) were a combination of these regions.
- Conclusion: Increasing medical students' awareness of their habituated face-touching behavior and improving their understanding of self-inoculation as a route of transmission may help to improve hand hygiene compliance. Hand hygiene programs aiming to improve compliance with before and after patient contact should include a message that mouth and nose touching is a common practice. Hand hygiene is therefore an essential and inexpensive preventive method to break the colonization and transmission cycle associated with self-inoculation.
This study found that even medical students who had recently completed education in hand hygiene, aseptic technique, and transmission-based precautions touched their face on average 23 times/hour. Forty-four percent of the touches involved the mucus membranes with potential introduction of contaminants with 36% involving the mouth, 31% involving he nose, 27% involved the eyes and 6% were a combination. This emphasizes the importance of hand hygiene to prevent infection.
So how can you stop the habit of touching your face? The first step is to be aware of the habit. Using a scented soap, hand lotion, or hand sanitizer will raise awareness when you get close to your face. Keep tissues available to avoid direct contact if you need to touch your face. Keep your hands busy, fold them, or keep them below the table or desk. Keep your elbows off the desk as this makes you more prone to touch your face. This is also probably one of the reasons masks are helpful, it prevents us from touching our faces. Finally, it's just a good idea to wash your hands frequently (or use hand sanitizer if water not available), just in case.
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How to Slow a Pandemic
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Could hand hygiene in airports slow the spread?
One of the things that makes global pandemics more likely is the frequency and ease that we can travel the world. Disease spread that used to take years now takes weeks. In 2017, 4.1 billion people traveled through airports worldwide. Airports are now the hubs playing a key role in the spread of disease. A disease can now start in one location and within days spread to multiple continents and within weeks cause an epidemic. Airports have inefficient air ventilation, people concentrated in confined spaces, and multiple surfaces frequently touched by passengers. P
ersonal hygiene is among the most important factors to prevent the spread of an infection
. Coughing etiquette, face masks
, no face touch, and hand hygiene are the most common actions that air travelers can easily adopt. From those actions, hand washing is simple and therefore is regularly mentioned as the first recommendation during disease spreading by the World Health Organization. This study analyzed contagion dynamics in the world air transport network and looked at the effects of hand washing on the spread of flu-type epidemics. Even small changes in the number of people exercising good hand hygiene could make large differences in spread of disease.
- The risk for a global transmission of flu-type viruses is strengthened by the physical contact between humans and accelerated through individual mobility patterns. The Air Transportation System plays a critical role in such transmissions because it is responsible for fast and long-range human travel, while its building components-the airports-are crowded, confined areas with usually poor hygiene. Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) consider hand hygiene as the most efficient and cost-effective way to limit disease propagation. Results from clinical studies reveal the effect of hand washing on individual transmissibility of infectious diseases. However, its potential as a mitigation strategy against the global risk for a pandemic has not been fully explored. Here, we use epidemiological modeling and data-driven simulations to elucidate the role of individual engagement with hand hygiene inside airports in conjunction with human travel on the global spread of epidemics. We find that, by increasing travelers engagement with hand hygiene at all airports, a potential pandemic can be inhibited by 24% to 69%. In addition, we identify 10 airports at the core of a cost-optimal deployment of the hand-washing mitigation strategy. Increasing hand-washing rate at only those 10 influential locations, the risk of a pandemic could potentially drop by up to 37%. Our results provide evidence for the effectiveness of hand hygiene in airports on the global spread of infections that could shape the way public-health policy is implemented with respect to the overall objective of mitigating potential population health crises.
I think we all know that airports are not the most sanitary places. I have always washed my hands at least prior to boarding and immediately after landing and it seems my instincts were absolutely correct. This study estimates that only 20% of the airport population have "clean hands". This analysis found that increasing this number to 30% could reduce spread of a potential infectious disease by 24%. Increasing this number to 60% at all airports in the world would decrease potential disease spread by 69%! It's incredible that a simple behavioral change could have such wide effect. Prior to our current pandemic, the worldwide spread of severe infectious disease was estimated to cause approximately 720,000 deaths per year and an annual reduction of economic outcome of $500 billion. Obviously, our current pandemic makes this amount of financial loss a rounding error.
While hand hygiene is considered the first prevention step in the case of an epidemic emergency, the capacity of hand-washing facilities in crowded places including airports is limited only to wash basins at restrooms. New technology is being developed aiming to increase the capacity of facilities even outside restrooms, thus expanding the options for hand hygiene and the solutions for air and surface sterilization. Airbus is exploring an innovative antimicrobial technology that is able to eliminate viruses and pathogens from aircraft surfaces (e.g., tray tables, seat covers, touch screens, galley areas). Boeing is also exploring a prototype self-sanitizing lavatory that uses ultraviolet light to kill 99.99% of pathogens. The current pandemic will certainly move these technologies forward. In the future a combination of increased awareness of the importance of hand hygiene, avoidance of facial touching, more hand washing/hand sanitizer stations, and improved cleaning/disinfectant technologies will help to mitigate the rampant spread of infectious disease.
Nicolaides, C., Avraam, D., Cueto-Felgueroso, L., González, M.C. and Juanes, R. (2020), Hand-Hygiene Mitigation Strategies Against Global Disease Spreading through the Air Transportation Network. Risk Analysis, 40: 723-740. doi:10.1111/risa.13438
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Thank you for taking the time to read through this newsletter. I hope you have found this information useful as we work together to optimize your health. Feel free to pass this on to anyone you think would benefit from this information.
You can find previous newsletters archived on my website here.
As always, if you have questions about anything in this newsletter or have topics you would like me to address, please feel free to contact me by
email
, phone, or just stop by!
To Your Good Health,
Mark Niedfeldt, M.D.
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