COVID-19 antibody test

“A positive test result shows you may have antibodies from an infection with the virus that causes COVID-19. However, there is a chance a positive result means that you have antibodies from an infection with a virus from the same family of viruses (called coronaviruses), such as the one that causes the common cold.”

Common Human Coronaviruses

Common human coronaviruses, including types 229E, NL63, OC43, and HKU1, usually cause mild to moderate upper-respiratory tract illnesses, like the common cold. Most people get infected with one or more of these viruses at some point in their lives. This information applies to common human coronaviruses and should not be confused withcoronavirus disease 2019 (formerly referred to as 2019 Novel Coronavirus).

last reviewed:  February 13, 2020

Test for Past Infection

Antibody tests check your blood by looking for antibodies, which may tell you if you had a past infection with the virus that causes COVID-19. Antibodies are proteins that help fight off infections and can provide protection against getting that disease again (immunity). Antibodies are disease specific. For example, measles antibodies will protect you from getting measles if you are exposed to it again, but they won’t protect you from getting mumps if you are exposed to mumps.

Except in instances in which viral testing is delayed, antibody tests should not be used to diagnose a current COVID-19 infection. An antibody test may not show if you have a current COVID-19 infection because it can take 1–3 weeks after infection for your body to make antibodies. To see if you are currently infected, you need a viral test. Viral tests identify the virus in samples from your respiratory system, such as a swab from the inside of your nose.

What do your results mean?

If you test positive

• A positive test result shows you may have antibodies from an infection with the virus that causes COVID-19. However, there is a chance a positive result means that you have antibodies from an infection with a virus from the same family of viruses (called coronaviruses), such as the one that causes the common cold.

• Having antibodies to the virus that causes COVID-19 may provide protection from getting infected with the virus again. If it does, we do not know how much protection the antibodies may provide or how long this protection may last.

• Talk with your healthcare provider about your test result and the type of test you took to understand what your result means. Your provider may suggest you take a second type of antibody test to see if the first test was accurate.

• You should continue to protect yourself and others since you could get infected with the virus again.

  • If you work in a job where you wear personal protective equipment (PPE), continue wearing PPE.

• You may test positive for antibodies even if you have never had symptoms of COVID-19. This can happen if you had an infection without symptoms, which is called an asymptomatic infection.

If you test negative

• You may not have ever had COVID-19. Talk with your healthcare provider about your test result and the type of test you took to understand what your result means.

• You could still have a current infection.

  • The test may be negative because it typically takes 1–3 weeks after infection for your body to make antibodies. It’s possible you could still get sick if you have been exposed to the virus recently. This means you could still spread the virus.

  • Some people may take even longer to develop antibodies, and some people who are infected may not ever develop antibodies.

If you get symptoms after the antibody test, you might need another test called a viral test​.

Regardless of whether you test positive or negative, the results do not confirm whether or not you are able to spread the virus that causes COVID-19. Until we know more, continue to take steps to protect yourself and others.

Learn more about using antibody tests to look for past infection.

last reviewed:  June 30, 2020

Development of Face Processing

…The development of face processing during infancy and childhood is one of the most extensively researched topics in perceptual development (6, 32). There is general agreement that face processing begins at birth because newborns: prefer face-like stimuli (see figure 2) to non-face stimuli (4); imitate another’s facial movements (33); prefer familiar over unfamiliar faces (34, 35); and attend to attractive over unattractive faces (36). However, some of these preferences at birth may reflect newborns’ general tendency to look at certain stimulus-general configurations that happen to be similar to faces (37). Despite this early start, researchers also agree that face expertise development is protracted with some investigators arguing that children reach adult levels only after puberty (38). More recently, however, Crookes and McKone (39) suggested that the face processing system was already very much mature by 5-6 years of age. The extensive literature notwithstanding, surprisingly, the role of experience in the development of face processing ability has until recently received little attention.

…This review of the developmental literature reveals early competence in face processing abilities, with infants presenting a preference for face stimuli and facial discrimination using featural, configural, and holistic cues. This early competence is then later refined as evidenced by age-related changes throughout childhood. Some of the refinements are likely due to the development of general cognitive abilities, whereas some others (e.g., configural processing) may be face-specific.

Although biological factors may initially play some role in biasing the newborn’s visual system towards faces in their environment, the existing evidence overwhelmingly suggests the important role of experience in the development of face processing expertise. The role of experience has been implicated in all aspects of the development of face processing expertise and from infancy through childhood. For example, it is evident that experience plays a crucial role in infants’ discrimination and children’s identity judgments for different categories of faces (i.e., species, race, gender, age), with better recognition abilities for the more familiar face categories (i.e., own-species, own-race, female, and own-age). However, considering the quasi-experimental nature of the existing studies, well-controlled experiments that directly manipulate experience (e.g., training studies) are needed to establish fully the causal linkage between differential experience and the development of face processing abilities.

The present review of the existing literature on the development of face processing has also revealed significant gaps in our research endeavors. While most of the recent exciting discoveries have been made with infants in all aspects of face processing, relatively limited knowledge has been gained about childhood face processing abilities, except for the development of facial configural processing. Future studies need to examine how children’s classification of faces at the basic and various subordinate categorical levels develops with age and to what extent such classification is related to their increasing abilities to process faces at the individual level, which in turn will provide a more comprehensive developmental account of the formation of face processing expertise.

COVID-19 risk reduction practices

[Easy to discuss, harder to put to text. Will update later. but synthesized from ongoing conversations, things posted on this blog and principals of reason. -rws]

A Framework of Thinking

As part of the discussion of reducing risk, it is advised to have some manner in which risk is quantified and what is an acceptable amount of risk to incur. The acceptable amount of risk may vary from individual to individual. What follows is one possible example of quantifying risk.

1) Risk Index (Ri)
Based on available science and reasoning, assign numeric risk value to respective scenarios. This number might be on a scale of 0-100. Using an ATM might be a 5, talking with a person two feet away might be a 30.

2) Risk Multiplier (M)
This numeric is to quantify increased risk due to increases in or contact points or person. For example if talking with a person has a Risk Index of 30 then talking with 3 people might be M*Ri or in this case a value of 90.

3) Risk duration/time. (T)
This might be represented by the number of minutes exposed to or involved in the risk scenario.

4) Raw Risk Value. (Rv)
Recognize that actual risk is a function of time exposure/duration (T) and the Risk Index (Ri) and Risk Multiplier (M). In the absence of other information presume. Rv=T*M*Ri

5) Risk Reduction/Mitigation Factor (Mf)
This number is to represent the effectiveness of mitigation efforts. For example a cloth mask that has 30% effectiveness in reducing aerosol contaminants, would equate to a  0.70 risk reduction/mitigation factor.

6) Risk Value (Rv)
For each scenarios the total Risk Value would be Rv = Mf*Rv
Going back to the three person meeting, this model would generate the following figures below:

2 hours duration
Rv 10800 without mask
Rv 7560 with mask

1 hour duration
Rv 5400 without mask
Rv 3780 with mask

Although this particular risk model is an example, it illustrates that with proper modeling it might be understood that reducing time of an event could have more positive impact on risk reduction than the mitigation from wearing of masks. This is an argument for the need to have a functional risk assessment model so that proper choices can be made.

7) Total Commutative Risk (Tcr)
This would represent the total period’s (day’s) worth of Risk. Essentially a summation of the days individual assortments of Risk Values (Rv) computed as indicated above. This figure would represent a total cumulative numeric of the days risks, including duration, quantity, and mitigation, etc. Tcr = ΣRv

In order to effectively reduce Total Cumulative Risk, one must have some framework on how risk is quantified, and what factors might mitigate or reduce risks. There may be cases where avoidance or elimination is the only way to drive the Total Cumulative Risk to an acceptable level. The focus should not be on the optics of Risk Reduction but instead on the actual reduction of Total Cumulative Risk. Having some model to represent Total Cumulative Risk may assist in this effort. A 30% reduction in an large risk may be unacceptable and best resolved by avoidance, a 90% reduction in an insignificant risk may be meaningless and waste resources that are best applied elsewhere. The costs, risks, and problems of mitigation efforts should be weighed against the results of mitigation efforts and their alternatives.

Concepts - Individual Choice

Reduce number of touch points.
Reduce number of social interactions.
Reduce occurrence of being in shared airspace.
Reduce duration of suspect events or circumstance.
Reduce occurrence of suspect circumstance.
Mitigate the above as necessary, appropriate and most effective:
sunglasses can be detrimental in the dark.
pool arm-floaties are of little use while hiking (and can cause chaffing).

Quarantine for safety if appropriate.
Quarantine to reduce uncertainty if appropriate.
Sanitize contact points (wash your hands not your elbows, or doorknobs).
Pursue environment and circumstance known to have less risk.
Pursue good health and a strong immune system.

Life in 3-D

Density
Distance
Duration

Evaluation of Risk Reduction Efforts

Items of consideration: Existing Risk Factor, Risk Reduction/Mitigation Factor (effectiveness), Ease of implementation, Cost, etc.

[this text is a work in progress. -rws]

Things Practiced Implement / Reasoning/ Sustainability

2020 January (got an early start on efforts, because of December cold/flu concerns)
Practice: Began effort to the break habit of touching face, eyes, mouth, nose.
Reason: Easy to implement. Science clearly indicated common infection path.
Sustainability: Can do this long term. No need to stop.
Comments:

2020 February
Practice: Began decontamination practices between appointments and activities. Liberal use of Isopropyl Alcohol (91%), and keeping separate materials (fresh/used cleaning cloths, items picked up/delivered, etc) to avoid cross contamination. Made conscious decision to not wear gloves as consider frequent decontamination of hands more effective and having less detrimental effect than wearing gloves.
Reason: Easy to implement. Science supported Isopropyl as a superior decontaminate.
Sustainability: Can do this long term. No need to stop.

2020 March
Practice: Began recording daily temperature reading (had only previously be spot checking and not recording).
Reason: Easy to implement. Science indicated even a mild infection has high correlation to an elevated temperature.
Sustainability: Can do this long term. No need to stop.
Comments:

2020 April
2020 May
2020 June
2020 July
2020 August

2020 September
Would make sense to incorporate into the above external conditions.
re:
https://www.isitzen.com/blog/2021/2/weather-impact-on-airborne-coronavirus-survival-physics-of-fluids

2020 October
2020 November
2020 December

2021 January
2021 February
2021 March
2021 April
2021 May
2021 June
2021 July
2021 August

2021 September
Here we are, marking what might be called 39th bi-monthly celebration of flattening the curve. Over a year since this original posting, yet still with on-going mandates based more on optics and bad data models then actual science.

[work in progress. expanding as time permits. -rws]

Handkerchiefs, Disposable Tissues, and Masks

I got curious about the old fashion handkerchief. (Perhaps because disposable tissues just seem too small and thin for me, but mostly because they were commonly used decades ago, and that got me thinking.) There seems to be little scientific data on the fair comparison between use of cloth handkerchiefs, disposable tissues, and cloth/surgical masks as it relates to influenza. And there seems to be no clear scientific study that points to why handkerchiefs fell out of favor. (At least none that I could find.) Not to long ago:

Influenza is in a highly contagious disease which may be caused by one of a whole family of viruses. A flu virus is spread through coughs and sneezes, and by contact with surfaces where the droplets thrown out by coughs and sneezes have settled. A flu vaccine grants temporary immunity from one particular variety of flu, but does not provide protection from the others. Washing your hands will reduce the chance of infection, and using a handkerchief will reduce the chance of spreading the virus to others.

There only seems to be anecdotal evaluation of cloth handkerchiefs where it is assumed that one uses it multiple times, that it is kept in a pocket with other items, is touched by hands and objects throughout the day, and is shared with others. (It is not difficult to discard an unclean handkerchief for later wash/reuse and to rotate in a clean replacement.) Contrast that to discussions of disposable tissues where usage assumes that the used tissue is disposed of promptly and the person washes their hands immediately. This is an unfair and misleading comparison. It would be interesting to see a fair comparison of the single use of a cloth handkerchief to a disposable tissue for both ambient airborne particulate dispersal and amounts of particulates on hands.

There is, however, some scientific evidence that there is little difference in small particulate and aerosol dispersal between coughing/sneezing into one’s hands, tissue, or elbow/sleeve. I was surprised by that. It would be interesting to see a scientific comparison of a single use cloth handkerchief against coughing into hands, tissue, and elbow/sleeve. It seems a resonable hypothesis that the cloth handkerchief would perform better than all three. It seems prudent to identify and practice the best manner in which to contain potential pathogens from a cough or sneeze.

As it relates to cloth and surgical masks, it seems interesting that handkerchiefs are considered unsafe because it is presumed that they are used throughout the day with multiple coughs and sneezes and touches by hands, and yet that approximates the results of mandated long term/continual mask usage as prescribed/observed.

If influenza transmission from an infected person is believed to correlate with the density of infectious virus material in a particle and/or surrounding airspace, size of particle (droplet or aerosol), depth of inhalation, and duration of exposure, it also seems reasonable to consider a comparison of properly coughing/sneezing into a single use cloth handkerchief to that of a coughing/sneezing into a cloth/surgical mask. Again, if a primary concern is reduction of infected droplets from a cough or sneeze, then determining the most effective way to reduce that quantity, should be of scientific and personal interest.

Furthermore, if airborne and fomite transmission are areas of concern, it would be interesting to see comparisons of on-person quantity of pathogens/contaminants and aerosol dispersants between a subject that had been coughing/sneezing into single use handkerchiefs over a prescribed amount of time away from an area and time of testing, to a that of person in the same scenario solely wearing a cloth/surgical mask for same duration and testing. As pathogens that were contained by a handkerchief that is discarded are thereby no longer on person, it could be interesting to know how that differs from residual pathogens that may be retained in the mask and thereby potentially be released during continued wearing. (i.e. The pathogens collected into a handkerchief can be disposed of after use, whereas pathogens collected into the mask are on/in the mask for the duration. Presumably at a later time the handkerchief user would have less total contaminants on their person than the mask wearer all things being equal.)

The lack of scientific evaluation of proper handkerchief use, may be the result of the extremely effective marketing, popularity, ease of use, and presumed advantages of disposable tissues. However, in light of guidelines promoting long term continual wearing of cloth masks, and actual results from using disposable tissues, actual scientific analysis of effectiveness of cloth handkerchiefs for coughing/sneezing may be warranted. In the absence of a previous scientific study, it seems reasonable to revisit and revaluate the handkerchief. Perhaps someone will find it fit to study and compare effectiveness of a simple handkerchief compared to the other alternatives.

The above is not intended to be a statement against the best practices of appropriate wearing of N95 masks (which are a completely different class of protective measures and equipment) where the situation warrants, but rather an exploration of basic practices and consideration of options how they might compare in effectiveness and risk reduction to each other in ordinary real world scenarios as practiced in the long run, with consideration of difficulty, discomfort, and disruption to individuals and society as a whole. The larger conversation and practices of disease and COVID-19 prevention involves many factors of which masks are only a part (and generally considered the last line of defense) including:

avoidance/isolation (stay away from sick people/avoid people if ill)
proximity (social distancing)
duration (limiting time in uncontrolled/unknown areas)
ventilation (avoiding confined spaces with poor ventilation that are risky)
disinfecting/cleaning/washing
reduction/protection (tissues/handkerchiefs/masks/face-shields/goggles)
maintaining over-all health (sleep/diet/etc)
sunlight/Vitamin-D
environmental factors (fresh air/heat/humidity)
monitoring key indicators (temperature/cough/fatigue, etc)
and more that thought or science may reveal or make possible.

It could be argued that educated, responsible choices that focus on using several of the above to accomplish a cumulative risk reduction appropriate for the situation is more important and effective than any one method prescribed generically by mandate. In the meantime, I have added using good old fashion handkerchiefs to my ensemble and practices (many of those of which I plan on continuing well after COVID-19 subsides), and am still looking forward to the day we can refer to this time period as the “old abnormal”. -rws

Sunlight and Protection Against Influenza

Introduction

…Seasonal influenza has been with humans throughout history (Viboud and Epstein 2016). It imposes extreme costs on contemporary societies, with 2017-18 being a notable high outlier (CDC 2018). Beyond the significant discomfort to those it strikes, it saps productivity when individuals cannot work (Duarte et al. 2017) and absorbs health care resources (Schanzer and Schwartz 2013). Influenza also has less known long-range consequences. Notably, individuals exposed to influenza in utero have lower earnings as adults and are more likely to depend on government assistance (Almond 2006; Schwandt 2017), and are more likely to suffer from serious health problems later in life (Lin and Liu 2014). They are also more likely to have a heart attack (Kwong et al. 2018). Influenza is a type of viral respiratory infection. Traditional public health measures to combat it include vaccination (Maurer 2009; and White 2016) and paid sick leave to keep contagious workers at home (Barmby and Larguem 2009; and Pichler and Ziebarth 2016). Coincidental reductions in interpersonal contact (such as from holiday school closings and public transportation strikes) can also reduce prevalence (Adda 2016). Finally, a recent meta-analysis shows that ingested vitamin D pills help to protect against these types of infections (Martineau et al. 2017)].

Conclusion

…Sunlight, likely operating through the well-established vitamin D channel, plays a significant role in flu incidence. A recent meta-analysis of 25 randomized controlled trials of vitamin D supplementation (Martineau et al. 2017) demonstrated significant benefits of vitamin D supplements for reducing the likelihood that an individual will contract an acute upper respiratory infection. The current study considers sunlight as an alternate, natural path through which humans can and do secure vitamin D. This study's findings reinforce the Martineau et al. evidence that vitamin D protects against such infections. The Martineau meta-analysis imposed stringent criteria for including a trial, thereby ruling out a variety of confounding factors, such as selection effects. This analysis adds three findings to this literature. First, the relationship between relative sunlight and influenza is likely driven by late summer and early fall sunlight, and not by sunlight the rest of the year. Second, externalities of immunity contribute strongly to the protective effects of sunlight. Third, these externalities, the underpinnings of herd immunity, operate most forcefully at a middle level of population density. Apart from its methodological contributions, this study reinforces the long-held assertion that vitamin D protects against acute upper respiratory infections. One can secure vitamin D through supplements, or through a walk outdoors, particularly on a sunny day.

Masks-for-all for COVID-19 not based on sound data

Conclusions

While this is not an exhaustive review of masks and respirators as source control and PPE, we made our best effort to locate and review the most relevant studies of laboratory and real-world performance to inform our recommendations. Results from laboratory studies of filter and fit performance inform and support the findings in real-world settings.

Cloth masks are ineffective as source control and PPE, surgical masks have some role to play in preventing emissions from infected patients, and respirators are the best choice for protecting healthcare and other frontline workers, but not recommended for source control. These recommendations apply to pandemic and non-pandemic situations.

Leaving aside the fact that they are ineffective, telling the public to wear cloth or surgical masks could be interpreted by some to mean that people are safe to stop isolating at home. It's too late now for anything but stopping as much person-to-person interaction as possible.

Masks may confuse that message and give people a false sense of security. If masks had been the solution in Asia, shouldn't they have stopped the pandemic before it spread elsewhere?