Victor Luca 15-Aug-20.
COVID-19 can be transmitted through contact (fomites), droplets and via aerosols (airborne). Yet, our Ministry of Health (MoH) took five months to wake up to the last of these and recommend masks. Yet, almost every photo of the 1918 pandemic shows people wearing masks.
If you go onto the New Zealand Ministry of Health’s web page now you will find recommendations and guidance on Covid-19 and the use of face masks. This was however, not always the case.
What you will no longer find on the site is a document dated 15-May-20 entitled “Review of science and policy around face masks and COVID-19” that could have be downloaded from the web page until at least June. Whilst by its title the document clearly purported to review the scientific literature and policy up to its publication date, it also cautioned in its first paragraph that it was not an exhaustive, systematic review of the scientific literature. Bit of a contradiction don’t you think? In fact that document was seriously deficient, omitting important recent research and evidence on COVID-19 transmission and mask use. The document now seems to have been removed but I include it below for completeness.
Until very recently our MoH was not recommending the use of face masks by the general public consistent with the spirit of the above cited document. The MoH considered face mask use entirely optional. Then on 7-Aug-20 everything suddenly started to change when Health Minister, Chris Hipkins, announced that Kiwis would be encouraged to wear a mask in public places if the country moved back to level two, and has recommended us to make our own if necessary. An abrupt about face (pun intended) considering the denials on the issue that stretched back to the beginning of the COVID-19 outbreak.
Let’s just take a quick look at the time-line in regards to advice on COVID-19 transmission and masks.
As at 2-Apr-20 the United States Centers for Disease Control & Prevention (CDC) were insisting that COVID-19 was transmitted “Through respiratory droplets produced when an infected person coughs or sneezes” and was talking of maintaining distances of 6 feet; not that I am sure where they got this arbitrary number from. Totally absent was the notion of aerosol transmission, despite the fact that this mode is proven to be an important mechanism in the spread of many infectious diseases that possess virus particles (virions) that have similar size, morphology (shape) and density to the SARS-CoV-2 virion responsible for COVID-19 disease. Included in that list is smallpox, chickenpox and measles. Another virus that after decades of scientific debate can now be included on the list of diseases for which aerosol transmission is considered important is influenza A. Disregarding potential differences in the amount of each virus required to give you these diseases, simple chemical-physical principles suggest that SARS-CoV-2 virions could remain suspended in air indefinitely depending on air flow and other conditions.
And yet it took until 14-Apr-20 for the CDC to start changing its tune on transmission and its guidance on face masks. It began recommending that, “in addition to social distancing measures, all Americans should wear masks when leaving the house for essential trips such as going to the grocery store or the pharmacy.” Touché! Finally they got there.
Regarding the World Health Organization (WHO), as at 29-Mar-20 they were stating “According to current evidence, COVID-19 virus is primarily transmitted between people through respiratory droplets and contact routes.” In fact until July the WHO continued to insist that COVID-19 was transmitted mainly by fomites and “droplets” (particles >5 – 10 µm in diameter). Little mention of even the possibility of aerosols and airborne transmission! Another prestigious institution downplaying the possibility of aerosol transmission, although their language was somewhat guarded.
COVID-19 is a respiratory disease and hence it would seem that breathing virus-contaminated air is a good way to become infected. An airborne virus – one in which tiny virus particles remain suspended in the air - can be taken directly into lungs and be absorbed onto the alveoli that line these organs. This seems obvious. Call it common sense even! The reason the above named institutions have been coy about aerosol transmission is that the implications of an airborne virus are serious and that the scientific evidence of airborne transmission was not regarded as conclusive, ironclad.
In the nuclear industry, in which I have worked for more than two decades, we are used to dealing with airborne nuclear contamination.
Viruses and radiation are similar in some important ways. Certain radioactive elements – those that emit gamma radiation - can irradiate you at great distances. Strong gamma-emitting elements require you to put a thick piece of lead shielding between yourself and the source in order to be safe. The radiation from alpha-emitting elements on the other hand typically cannot even penetrate even a piece of paper. Nevertheless, contamination by alpha emitters is deadly and is similar to viruses in that the elements can be transported by tiny invisible dust or vapor particles suspended in the air and can be drawn straight into the lungs by breathing. This is termed an inhalation risk, as opposed to an ingestion risk. Once in the lungs, radioactive elements carried on tiny dust or vapor particles can be taken into the blood stream and there cause their damage at close quarters just like an airborne virus. The mantra of radiation protection is ‘Time, Distance and Shielding’. That is, reduce exposure time, increase distance and put something – shielding - between yourself and the radiation. Where there is an inhalation risk such as contaminated dust, then respiratory equipment should be used. Just like for an airborne virus.
Despite the evidence that was accumulating for airborne transmission of COVID-19 from the start of the outbreak, our MoH downplayed, or even ignored, the possibility of airborne transmission and dismissed the potential benefits of face masks saying “they might do more harm than good”.
New Zealand's director of public health, Dr Caroline McElnay, on 5-Apr-20 is on record as saying "Any face masks worn by the community at large would have to be right at the bottom of our strategies for containment of Covid-19 based on the information we have about the effectiveness of strategies."
In June I exchanged numerous e-mails with the MoH arguing the importance of airborne transmission and the case for mask use. They fobbed me off by pointing me to the document I referred to above entitled “Review of science and policy around face masks and COVID-19”. I had spent months reviewing the scientific literature on COVID-19 transmission since the start of the COVID-19 outbreak to come to the conclusion that there was no way of ruling out, a prior, airborne transmission.
In respect of airborne transmission and face masks the MoH seemed to be waiting for definitive evidence in the form of randomized double-blind trials that are difficult, if not impossible, to perform in a reasonable time frame to test airborne transmission and the utility of masks. However, there was always strong indirect evidence to suggest the potential importance of airborne transmission and the use of masks as I pointed out above. In an article I published with a colleague on 8-Apr-20 in our local paper, The Whakatāne Beacon, we came to the conclusion that airborne transmission of the SARS-CoV-2 virus could potentially be important and we recommended the use of face masks to our community. We used an argument by analogy. We argued that since the viruses of other diseases, which are of similar size and morphology to SARS-CoV-2, could be transported large distances in the air, then why not SARS-CoV-2? We figured it was best to be guided by what science there was at the time and err on the side of caution rather than wait around for definitive proof which could take decades as it did in the case of influenza A.
On 5-Aug-20 Dr Bloomfield came out with his, “it’s not if, but when COVID-19 returns” proclamation. By Wednesday of the following week, cases had been detected in South Auckland and we are now aggressively contact tracing trying to bring this outbreak under control and identify the cause.
How our MoH missed the obvious on transmission and masks is beyond me and is extremely concerning. After doing science for more than three decades, I have learned to be skeptical and to challenge current wisdom and also to be very careful in reviewing evidence. When it comes to pandemics we must always be challenging assumptions and weigh the evidence up very carefully. Most of all, we should be guided by the science.
When it comes to something with such huge public health, social and economic implications and consequences as a deadly pandemic then ‘discretion is the better part of valor’. In other words, when you are not sure, err on the side of caution!
The same could be said of the spread of COVID-19 by children. Once again, our MoH is waiting for definitive proof that children spread COVID-19 before they close schools. To this the adage ‘Absence of evidence is not evidence of absence’ is certainly applicable. The data on this is already clear and initial suggestions that children don’t spread the virus is pure wishful thinking.
The final piece of nonsense that I wish to treat is the idea that a distance of a meter or two has some special significance. Yes, the more distance the better. However, two meters will be of relatively little value if this virus is airborne and you are sharing air in an in enclosed space with a COVID-19-infected person.
New Zealand is an island nation with a low population density and we are an obedient lot, and by and large, we have faith in our leaders and experts. We managed by a combination of good luck and good management to eliminate the virus in the first innings and for this I am truly grateful. As a consequence, few people died of this virus in our country. If we keep our guard up and use our heads we can continue like this and get about our business in a relatively normal manner. I wrote weeks ago, again in our local paper, that another round of COVID-19 was inevitable and here it is. Now I hope we are smart and err on the side of caution. There is certainly no room for poor scholarship and sloppiness or incompetence by our experts. I know I am being hard on our MoH but this is a serious disease and there is little margin for error. Being careless, fool hardy and sloppy can have consequences.
Wearing masks is not a great imposition considering what is at stake. The Chinese knew this from the beginning while we were in denial.
The third session of the 13th National People's Congress at the Great Hall of the People in Beijing on 22-May-20 showing every single member wearing a mask.
Note added in proof: Despite the reluctance of the WHO and United States Centers for Disease Control and Prevention, it is clear that someone had told Donald Trump the truth about COVID-19 transmission. After all, he could never have worked it out for himself.
References
[1] Review of science and policy around face masks and COVID-19. 15-May-20.
[2] Brosseau, L. COMMENTARY: COVID-1 9 transmission messages should hinge on science. CIDRAP, 16-Mar-202.