More than 200 respiratory viruses are responsible for what is colloquially called “the common cold”. All of them are seasonal to some degree. Enveloped viruses (so called because they are surrounded by an envelope of lipid) peak in winter because the cold dry air provides an optimal environment for viral transmission. Heat, humidity and possibly sunlight appear to damage the lipid layer, making these viruses less viable. The enveloped Coronavirus responsible for Covid-19, genetically related to two Coronaviruses which cause the common cold, is expected to peak in winter, as the world has observed so far.
Despite close connections with China and significant travel between the two countries, Covid has barely touched the Cambodian population. The first case of Covid-19 in Cambodia was a Chinese man from Wuhan. He was diagnosed in late January, four days after arriving in the country with his family. Contact tracing identified no local transmission. Since then only very few cases of local transmission have occurred at all, with almost all diagnoses occurring in arriving travelers, some of whom had gone home to their families before being contact traced or otherwise identified and tested. Almost all cases, as with most cases worldwide, have been asymptomatic or mild and so far there has not been a Covid death in Cambodia.
Recently a case who arrived in Cambodia from America escaped isolation, attending restaurants, hotels, shops and even spent hours in a beauty parlour before she was relocated some days later and placed back into isolation. Those she had potentially exposed were all quarantined for two weeks, no doubt causing significant hardship. None contracted the virus from her. This is a practical example showing that the much-talked-about “reproduction number” (R0) is not a static number. The R0 for Covid-19 may average at 2.5 (meaning each case transmits to about 2.5 other people), but it is influenced by complex dynamics involving environment, population susceptibility, viral dose and other factors so it may be much higher in some circumstances and much lower in others.
Influenza is also an enveloped virus which appears to have some, but not a lot of, impact in Cambodia. Apparently one of the Big Pharmaceutical companies aggressively marketed their influenza vaccine in Cambodia about twenty years ago, to no avail.
Environment is not the only reason that the virus may not transmit in some populations. Population immunity is another possibility. In an interview with Freddie Sayers at Unherd.com, Professor Michael Levitt describes his journey exploring Coronavirus since he first started documenting his observations in January. One of his observations was that the death rate in Hubei Province was much higher than the death rate elsewhere in China. The death rate also began to slow quickly with no clear explanation as to why, but prior immunity was one of the possibilities.
None of these theories are new to disease investigation and control. Organism factors (eg lipid envelope), host factors (eg immunity) and environmental factors (eg climate) are depicted in the very basic but informative epidemiological triangle, referred to in epidemiology studies since at least 1928. Yet during Covidmania people daring to talk of such things, or out of line with mainstream media, are condemned as somehow radical or anti-science. It seems an amazing phenomenon until you think about the historical experience of science. For example “On June 22nd, 1633, Galileo was shown the instruments of torture by the Inquisition and threatened with their use unless he recanted his expressed view that the Earth revolved around the Sun, instead of the other way round” (From Adam Smith Institute).
Despite their good fortune virus-wise, Cambodians are nevertheless suffering because of Covid. Tourism has dwindled to nothing, daily workers have lost their incomes, garment factories, restaurants and hotels have closed, tuk tuk drivers have no customers. One of my friends lives in a small house in a slum alleyway with a family of seven people. Their income previously included rent of a family home but the tenant lost their job and moved out, and the home has remained vacant for months. My friend’s monthly salary is now the sole family income and she forfeits breakfast daily in order to survive the month. This family are relatively prosperous compared to most.
It is difficult to predict when those responsible for public health in Cambodia (including World Health Organisation and Ministry of Health) might start changing their messages of fear to messages of normality. Private and international schools serving only the wealthiest have returned to class whilst state schools remain closed. Most state school students have no access to the technology needed to study from home. Today’s headlines announce scaling-up of Covid-19 testing laboratories across the country whilst the diseases of poverty that do kill Cambodians are increasingly neglected.
The disproportionate allocation of resources and unequal value of one death (or life) over another is not specific to Cambodia. US CDC lists twenty Neglected Tropical Diseases (NTDs) which affect 1 billion people across Africa, Asia and South America. Every year NTDs kill 500,000 people. Additionally they cause disfigurement, disability, poverty, stigma, marginalisation and significant community and national economic loss. Yet “Since the start of the COVID-19 crisis, more diagnostic tests have been developed for SARS-CoV-2 than for all 20 NTDs in the last 100 years.“
Some other pandemic proportions include:
“The city of Chicago invested nearly $120 million on four separate emergency coronavirus facilities in the spring that ended up treating a total of 38 patients, bringing the effective price tag of the massive project to over $3 million per patient.”
Currently in Denmark 25,000 to 30,000 people are tested daily for Covid. Of these between 100 to 160 have a positive result. That’s an upper limit of 0.64% positivity with a high chance of false positives due to the low infection rate. Currently 14 people are in Danish hospitals with Covid and 0 in ICU. Masks are about to become mandatory on public transportation and further restrictions are being considered.