The Coronavirus Pandemic: Evidence from Virology and Immunology

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Here are some thoughts as I look at some of the available information in pursuit of some usable understanding of the COVID-19-causing novel coronavirus SARS CoV-2, and what we can and must do about it. Open access to research has been a blessing and a curse, as preprints which have yet to be peer reviewed have attracted uncritical attention.

Epidemiology

First, the numbers. From the early stages, politics, national pride, and concern about arousing fear and panic, have contributed to serious doubts about how many are infected, how sick and in what way, and how many deaths have resulted. Data need to be presented as per capita, not just absolute numbers. And even if every single person were to be tested, no country or jurisdiction is homogeneous, particularly in terms of the so-called social or structural determinants of health. Data collection is just beginning to count race or ethnicity, while neglecting the systemic realities of living circumstances (population density, housing, adequate water and food, access to healthcare, stress, exposure to violence, etc.)

The number of cases has been the least reliable variable, as it depends on the number actually tested. Tests vary in availability, and in terms of sensitivity and specificity. Further, there have been a few cases where the infection resides lower in the respiratory tract, with negative nasopharyngeal swab results. Some patients can carry the virus and show no symptoms, some can carry it for weeks, and some appear to have survived the illness, only to test positive again (which may be due to dead virus, i.e., no longer infectious).

The disease process and manifestations

The COVID-19 disease reflects the interaction of the virus and the delicately complex immune response. The disease itself manifests in an increasing variety of ways. Currently, the understanding is that it can cause inflammation of blood vessel lining (endothelium), causing clot formation, affecting a variety of organs, including lung, heart, kidney, brain, and skin.

Individuals may test positive for antibodies (and there are different types), but so far this does not guarantee immunity, or absence of viral shedding (infectiousness). The frantic pursuit of a vaccine is highlighting not only the antisocial behaviours in the (nationalistic) marketplace, but the complexity of the immune system.  Some vaccines may end up producing short-term or insufficient responses, or unintended effects; hence the potentially lengthy wait until one is available.

And if an effective vaccine becomes available, will it be accessible? Will it be manufactured in sufficient quantities for global distribution? Will it be proprietary, for profit, expensive? Will it be stable and transportable to regions without requiring refrigeration? Will administration require hypodermic needles? Will health personnel be available, or be deterred by armed conflict or militarized borders? Will there be sufficient nutrition and biological resilience so that individuals can mount a sufficient response? Or will some individuals mount a hyper-immune response, attacking their own bodies?

Staying safe

In the meantime, the best protection continues to be physical distancing, hand washing, and masks and eye protection to be extra cautious. Droplets appear to be the primary, but not the only, mode of transmission. Two meters separation is advised, though one source recommends staying 65 feet behind a cyclist. And what about opening up? Experience with previous pandemics, uncertainty around numbers, and the precautionary principle all indicate that this virus may be around for a long time, and that despite isolating and remaining free from infection thus far, individuals remain susceptible. Returning to normal activities (and there are multitudes who in our current economy do not have the choice) exposes one to the possibility of a very serious disease that can cause lasting impairment or death.  In a number of countries and jurisdictions, a social experiment is being carried out, and time will tell – with up to several weeks until conclusions can be drawn, too late for some.


Jim Deutsch, MD, PhD, FRCPC, is a physician trained in biochemistry teaching at the University of Toronto, and a Board Member of Science for Peace.

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