Covid-19 Up Close and Personal

 On September 4, I started to feel typical symptoms of a flu-like illness. I have been a student of flu-like illnesses for at least the past 15 years. Some may say that I am obsessed with flu-like illnesses. By definition these illnesses start out as acute upper respiratory infections but also lead to systemic symptoms like malaise, weakness, and muscle pains or myalgias. In some cases, the symptoms can build to a disabling intensity. About five years ago I developed a flu-like illness after returning from Alaska that led to an exacerbation of asthma. I had not taken any asthma medications for 20 years but have been on those medications ever since. Researching that area suggested that flu-like illness was probably a rhinovirus. Some researchers think that rhinovirus is one of the main precipitants of asthma. Rhinovirus also happens to be a common circulating respiratory virus along with about 20 others that cause respiratory infections every year.  There are several non-COVID-19 coronaviruses in this group.

There were definite early signs even before the first respiratory symptoms. I have a fairly set exercise routine that I do every week and I noticed that my baseline heart rate (54 bpm) and blood pressure (105-110 mm Hg systolic) were increased and my exercise capacity was decreased by about 40%. That occurred about 48 hours before the onset of symptoms. As the symptoms increased my first thought was that I needed to get tested for coronavirus. That took an additional four days. It wasn’t from a lack of trying, but more a lack of resources going into the weekend. That delay highlights a significant weakness in the American healthcare system. I self-quarantined during that time but there are a lot of people who would need to see the test result before they could.  I did get positive test on day seven, I canceled the rest of the day at work and have been home recovering ever since.

The overall course of the illness has been very similar to a moderate case of influenza with the exception that I did not get a fever. It measured every day in the normal range. I also did not get shortness of breath.  Having the risk factors of asthma and old age, I was fairly anxious about any shortness of breath as a symptom. My symptoms are basically as graphed with a few exceptions of what I would refer to as atypical symptoms. The first one would be feeling flushed or like the skin temperature is elevated. That has been a fairly consistent feature that I have not seen mentioned anywhere. My skin was always cool to the touch and not moist. Another atypical symptom is laryngitis.  I have observed that in several COVID-19 patients in the media.  It can be fairly limiting if you have to talk all day at work like I do. The third atypical symptom was viscous mucus in the nose and throat. It was not abundant but difficult to clear and never reached the volumes typically seen in bronchitis.

One of the questions that I have been asked is: “How does a guy as careful as you end up catching COVID-19?”  It turns out that is an excellent question. As noted elsewhere on this blog I have essentially self-quarantined at home since the end of March or the start of the pandemic. I have had limited contact with people. I do not go into stores, supermarkets, coffee shops, or any public space. I pick up groceries ordered online and then collect them from a site where a masked attendant loads them into the back of my SUV.  All of my clinical work, continuing education, and professional meetings are done online.  I prepared a timeline of all contacts in or around my home for the previous 19 days (click to enlarge).  

From the summary, of the 18 total contacts I had direct contact with 6, only 4 of them about 6 days prior to the onset of symptoms.  All 4 of those contacts were wearing masks and none have tested positive for COVID-19.  My wife had contact with the other 12 and 9 of them were socially distanced or masked.  Only the electrician and three of the appliance repair/installers were not but they were socially distanced.  In addition, we made an effort to air out the house when they were there and after the left.  There was a total of 5 tradesmen in the house. They were all there for an average of about 1 hour.  I greeted one of them at a distance of about 12 feet and he was not wearing a mask. According to a recent hierarchy of transmission risk, I had no high-risk contacts for transmission (3).

My wife on the other hand was in a couple of higher risk scenarios (but not much higher).  As an extrovert, she was also out talking with people every day and exercising with several of her health club friends at their homes. She did however test negative for COVID-19 on the exact same test that I took. There are various estimates that 20-40% of COVID-19 infections result in asymptomatic carriers. It may be possible that she was a carrier and subsequently cleared the virus so that no viral RNA was detected on the nasal swab.  We are both currently trying to get antibody testing to COVID-19. It will confirm that I have short term immunity and possibly that my wife was an asymptomatic carrier.

When I did find out that I tested positive, I self-quarantined in the house pending my wife’s test and have been quarantined ever since.  The health plan recommendation is to wait for day 14 and if asymptomatic at that point, the self-quarantine can end. My wife is using the same date to end her quarantine and remained asymptomatic.  We have the luxury of having a large enough house where we can occupy separate areas and have separate bathrooms that are exhausted to the outside of the house.  I also kept an electronic air filter with a UVC germicidal light at the entrance to my office and between us in any public areas.  Several questions arise from this experience including:

1.  Why were my symptoms so mild (relatively speaking)?

Considering the actual statistics of the pandemic in the United States – my outcome is not that surprising.  About 1 in 34 cases have died and that number increases to 1 in 13 in my age range and 1 in 5 in the next highest age decile.  At the time of this posting there have been 197,000 deaths and 6.7 million cases.  There is a lot of comparison with influenza, but at this time there should be no mistake that while influenza typically generates more cases and more hospitalizations – there has only been one year where influenza mortality exceeded current SARS-CoV-2 mortality and that was the pandemic of 1918. 

The second consideration are the physical parameters of the environment. Assuming that my wife is not an asymptomatic carrier, the only time I was at a distance of less than 4 meters I was wearing a mask and so were the people I was in proximity to.  The contact lasted less than 10 minutes. And not a lot was said. We know that masks, distancing, and dilution in outdoor air probably works be reducing the concentration of airborne viral particles.  With that reduced concentration, any inhaled inoculum will be less resulting in a less severe infection. The estimated number of viral particles necessary to precipitate a case of COVID-19 is about 280 particles. That is 2-3 orders of magnitude higher than more virulent and lethal viruses like smallpox.

A few other lifestyle considerations. I eat a high-protein, high fiber, high whole grain, and low fat/low sugar diet.  I try to maintain a healthy weight.  I drink a lot of fluids every day.  I have been doing that for at least 30 years on the advice of a rheumatologist in order to maximize uric acid secretion and decrease the risk of gout attacks (I am an undersecretor of uric acid and had my first gout attack in medical school). Anyone reading this should drink a lot of fluid only based on their physician’s advice.  The only relevant factor in this paragraph in surviving the virus is probably maintaining a healthy weight and a good diet.  I was able to maintain my usual fluid intake during the course of this illness.

I take Vitamin D every day because my levels are typically marginal.  I take famotidine daily to prevent anaphylactic reactions. I only take it because the original H-2 antagonist recommended by my allergist (ranitidine) was taken off the market because of contamination in the manufacturing process. There has been some suggestion that famotidine is useful in the prevention or treatment of COVID-19 and for a while it nearly disappeared off the generic market.  I am not aware of any randomized clinical trial (RCT) results of famotidine and it has been demonstrated to not have any direct antiviral effect in vitro.  There is current speculation that in combination with H-1 antagonists that it may reduce histamine associated cytokine effects (13). At this point I would not consider it to be too relevant.

Exercise is a big part of my life and has been for the past 30 years. I typically exercise vigorously for 90 to 120 minutes per day.  Recent research (11,12) suggests that people who exercise vigorously into old age have better acute adaptive immunity (T-cell response) due to a better thymic environment.  One of the purported mechanisms is IL-7 production by skeletal muscle.  IL-15 is also an exercise responsive interleukin that enhances T-cell survival.  The net effect of these changes in the older person who exercises vigorously has a greater input of thymocyte progenitor cells and an enhanced output of CD4 and CD8 cells that are recent thymic emigrants (RTE). Both of these cells populations are critical for the acute adaptive response to novel viruses.  If I had to speculate about the lifestyle factors that are important it would probably be the effects of exercise, diet, not smoking and no alcohol intake on immunity and pulmonary function.

 2.  Why is there such heterogeneity in responses?

The host determinants of response are not well characterized at this point- other than the suggestion that previous exposure to common circulating coronaviruses could possibly lead to an enhanced antibody effect and either apparent asymptomatic carrier status or a less severe case as an adult.  Is it possible that the severe respiratory infection that I got in January was a coronavirus that was not SARS-CoV-2 and that it conferred some immunity?  This is one of the theories about why children are less affected by COVID-19 than adults – they tend to get more respiratory virus infections per year. Human coronaviruses and rhinoviruses are generally considered to cause up to 50% of common cold infections per year (10).  The Minnesota Influenza Incidence Surveillance Project, (MIISP) 3 of the 4 normally circulating human Coronaviruses – NL63, HKU1, and 229E (not OC43) since last September. Although these coronaviruses are now considered all part of the collection of common cold viruses they have been fairly recent discoveries with NL63 discovered in 2004 (7) and HKU1 discovered in 2005 (8).  The common coronaviruses have considerable RNA sequence homology with SARS-CoV-2 suggesting cross immunity can exist (9).  For example, pre-existing T-cell immunity in blood donors to SARS-CoV-2 is documented and is thought to be due to exposure to beta-coronaviruses that are in circulation (4).  But there is also evidence suggesting that pre-existing coronavirus immunity is not effective with SARS-CoV-2 (15).

One the genetic side, there are essentially no data at this point about genetic factors that favor successful recovery from the pandemic virus (click to enlarge).

 

3.  Given the exposures – is it possible that some other exposure (packaging, mail, aerosols from washing packing or mail) is more important than suggested by conventional wisdom?

Even though handwashing and washing of frequently touched surfaces is a top recommendation the current opinion is that transmission is unlikely from either groceries or mail based on studies that look at virus survival on different materials over time.  To me that is somewhat inconsistent with the hand washing advice.  The original theory was that a person could touch a contaminated surface, touch their face, and then end up with the infection through mucus membranes.  Groceries and the mail seem to be designated as infrequently touched surfaces relatively free from contamination.  An additional question for consideration is whether aerosols generated in washing the surfaces of groceries can transmit. SARS-CoV-2.  I use a UV sanitizer for mail and any objects the size of a large book or smaller. That method has limitations in terms of how accessible the surfaces of any contaminated object are.

One final critical consideration is the person you are in quarantine with. Do they share your goals and risk tolerance or not?  In my particular case, I am not risk tolerant at all if the risk is contracting a virus that has a 1 in 13 chance of killing me.  The prior probability of an adverse outcome is higher due to me having asthma, but the exact numbers are probably not known at this time. I would happily remain at home, not get a haircut (I have not), and just go out for groceries and necessary medical care.  My wife on the other hand is very social, and has maintained an active schedule with her friends and associates over the entire pandemic.  She spends her days exercising, socializing, and attending limited activities with friends.  She is distanced and wears a mask when necessary. Despite our ability to pick up groceries without having to enter a store she will spontaneously stop at these stores, put a mask on, and pick up a few items. This difference in approaches to the pandemic does create some tension.

Whether our different approaches produced predictable outcomes or not is up in the air at this point.  She was just approved for antibody testing and I still have to get approval at an appointment next week. All we know is that I was positive for SARS-CoV-2 on a PCR test and she was not. That leaves either airborne transmission, contaminated surfaces, or aerosols from washing contaminated services.

Getting through this does provide a sense of relief.  Even though immunity to this virus does not seem to be permanent at this point I am very grateful to have made it through these two weeks.  My boss sent me an email and asked what that sense of relief was like and I told him:

“It feels like I dodged a bullet.”

And it does…..

 

George Dawson, MD, DFAPA

 

References:

1:  Stephens DS, McElrath MJ. COVID-19 and the Path to Immunity. JAMA. Published online September 11, 2020. doi:10.1001/jama.2020.16656

2:  Gandhi M, Beyrer C, Goosby E. Masks Do More Than Protect Others During COVID-19: Reducing the Inoculum of SARS-CoV-2 to Protect the Wearer [published online ahead of print, 2020 Jul 31]. J Gen Intern Med. 2020;1-4. doi:10.1007/s11606-020-06067-8

3:  Jones Nicholas R, Qureshi Zeshan U, Temple Robert J, Larwood Jessica P J, Greenhalgh Trisha, Bourouiba Lydia et al. Two metres or one: what is the evidence for physical distancing in COVID-19? BMJ 2020; 370 :m3223 Link

4:  Stephens DS, McElrath MJ. COVID-19 and the Path to Immunity. JAMA. Published online September 11, 2020. doi:10.1001/jama.2020.16656 Link

5:  Fischer EP, Fischer MC, Grass D, Henrion I, Warren WS, Westman E. Low-cost measurement of face mask efficacy for filtering expelled droplets during speech. Sci Adv. 2020;6(36):eabd3083. Published 2020 Sep 2. doi:10.1126/sciadv.abd3083 Link

6:  Bar-On YM, Flamholz A, Phillips R, Milo R. SARS-CoV-2 (COVID-19) by the numbers. Elife. 2020 Apr 2;9:e57309. doi: 10.7554/eLife.57309. PMID: 32228860.

7:  Fouchier RA, Hartwig NG, Bestebroer TM, Niemeyer B, de Jong JC, Simon JH, Osterhaus AD. A previously undescribed coronavirus associated with respiratory disease in humans. Proc Natl Acad Sci U S A. 2004 Apr 20;101(16):6212-6. doi: 10.1073/pnas.0400762101. Epub 2004 Apr 8. PMID: 15073334; PMCID: PMC395948.

8:  Woo PC, Lau SK, Chu CM, Chan KH, Tsoi HW, Huang Y, Wong BH, Poon RW, Cai JJ, Luk WK, Poon LL, Wong SS, Guan Y, Peiris JS, Yuen KY. Characterization and complete genome sequence of a novel coronavirus, coronavirus HKU1, from patients with pneumonia. J Virol. 2005 Jan;79(2):884-95. doi: 10.1128/JVI.79.2.884-895.2005. PMID: 15613317; PMCID: PMC538593.

9:  Yaqinuddin A. Cross-immunity between respiratory coronaviruses may limit COVID-19 fatalities. Med Hypotheses. 2020 Jun 30;144:110049. doi: 10.1016/j.mehy.2020.110049. Epub ahead of print. PMID: 32758887; PMCID: PMC7326438.

10:  Greenberg SB. Update on Human Rhinovirus and Coronavirus Infections. Semin Respir Crit Care Med. 2016 Aug;37(4):555-71. doi: 10.1055/s-0036-1584797. Epub 2016 Aug 3. PMID: 27486736; PMCID: PMC7171723.

11:  Duggal NA, Pollock RD, Lazarus NR, Harridge S, Lord JM. Major features of immunesenescence, including reduced thymic output, are ameliorated by high levels of physical activity in adulthood. Aging Cell. 2018;17(2):e12750. doi:10.1111/acel.12750

12:  Lazarus NR, Lord JM, Harridge SDR. The relationships and interactions between age, exercise and physiological function. J Physiol. 2019;597(5):1299-1309. doi:10.1113/JP277071

13:  Hogan Ii RB, Hogan Iii RB, Cannon T, et al. Dual-histamine receptor blockade with cetirizine - famotidine reduces pulmonary symptoms in COVID-19 patients [published online ahead of print, 2020 Aug 29]. Pulm Pharmacol Ther. 2020;63:101942. doi:10.1016/j.pupt.2020.101942.

14:  Minnesota Influenza Incidence Surveillance Project,  (MIISP). Minnesota Department of Health.  Correspondence on circulating common coronaviruses in Minnesota.  Received on 9/19/2020. 

15:  Loos C, Atyeo C, Fischinger S, Burke J, Slein MD, Streeck H, Lauffenburger D, Ryan ET, Charles RC, Alter G. Evolution of Early SARS-CoV-2 and Cross-Coronavirus Immunity. mSphere. 2020 Sep 2;5(5):e00622-20. doi: 10.1128/mSphere.00622-20. PMID: 32878931; PMCID: PMC7471005. 

Supplementary 1:

My wife tested negative for SARS-CoV-2 IgG antibodies today (9/22/2020) in addition to the negative nasal swab PCR tests - making her an unlikely source of infection.

Supplementary 2:

COVID-19 follow-up: 

Saw my internist yesterday (9/25/2020). 

My course of the illness was "average" for all of the patients he has seen. He agreed that PCR false positives are not likely but false neg are. He declined Ab testing. I applied to the Red Cross convalescent plasma program.