Factors influencing Covid and or Flu seasonal surges
Introduction:
Understanding the minimum humidity verses Covid case numbers correlation graph for London.
This is a graph that can anticipate when Covid case numbers are likely to surge, flatten or fall. This will be particularly useful for monitoring Covid cases as U.K. Gov intends to stop publishing daily numbers of Covid cases.
One advantage of this association is it has remained consistent and reliable since records began for London in February 2020, irrespective of any variants or measures in place such as lockdowns, vaccines, social distancing etc.
(Background and details to this correlation can be found here:
The main key features of this correlation graph are its:
a) Simplicity.
(i) Easy to reproduce
(ii) Easy to interpret
b) Robustness.
As shown this graph has maintained integrity irrespective of numerous factors such as variants, any existing mandates, vaccinations, mask wearing, social distancing etc.
The correlation between Covid case numbers and minimum relative humidity depends on the lowest values of humidity during a circa 14-day period. These lower humidity values will be referred to as influential minimum humidity values for this correlation.
Influential minimum humidity values explained:
Influential minimum humidity values are simply discrete values of humidity which are derived from weather charts consisting of two to three of the lowest minimum humidity readings in a given 14-day period. These values represent the worst-case scenarios for Covid infection rates based on findings that show survivability, transmission and infection of the SARS-CoV viruses are highest when humidity is lowest and vice-versa. The 14-day interval starts at the lowest minimum humidity value expressed in the usual way as % observed in any given period. The procedure may start by looking through any continuous circa 17 days of humidity values in a weather report and choosing two or at most three of the lowest values. For example, if the readings for the 17-day period are 61, 55, 77, 65, 71, 66, 69, 72, 78, 67, 64, 59, 62, 73, 51, 56, 60. The set of influential humidity values that are relevant to this correlation are 55% and 51% on day two and fifteen because these are the lowest values. These can be placed in their respective days on the spreadsheet. Note that all other values can be ignored. Selection of the next set of influential values is derived by selecting the lowest humidity value in the next 14-day period which is counted from day with the lowest value ie counting from 51% in the above example. To find the influential values prior to day one, 55% is the starting point in the above example which is counted backwards. In other wards the starting point for any 14-day period is always the lowest minimum humidity value and you need at least two influential humidity value in any given 14-day period. The picture below illustrates how this is done in practice. Also included is a spreadsheet illustrating a live example of influential humidity values their selection and use in the Covid case numbers correlation over the last two years. Note that the correlation is relatively tolerant towards errors during its reproduction.
The weather chart for this example is chosen because it’s easy and straight forward to use and can be found here:
Otherwise, any other historical and live weather charts can be used to develop the correlation graph for example:
https://www.wunderground.com/history/daily/gb/london
Basic interpretation of the ‘epic graph’ based on observations over the last two years:
1. Main significant Covid wave:
The major significant surge in Covid cases occurs in December coinciding with the peak in influential humidity values as described above. The two most significant surges of Covid cases in London over the past two years occurred when the influential figure went above 65% with exponential rises in cases as this figure rose above this level peaking at the end of December and then cases started to drop rapidly and dramatically as the influential value dropped below 65%. Basing on two main Covid waves in the last two years it would appear in London at least influential values rising above 65% may signify a major exponential surge is in progress. This exponential surge is broken as soon as the influential value retreats to circa 65% and below.
The increase in influential value to 65% does not appear to happen suddenly rather there is a gradual build up that occurs beginning roughly August rising roughly linearly until it finally hits circa 65% in November. During this time Covid case numbers will also be increasing gradually and roughly linearly. Note that the drop back of the influential value to circa 70% and below after peaking happens within a short period of time i.e., within the space of two to three weeks, during which time Covid case numbers also fall sharply and dramatically signifying the end of the major wave.
2. Mini Covid wave:
As is the case in many countries notably India, any drop in the influential humidity figure or humidity below 20% appears to trigger a surge in cases. In London this maybe the cause of the mini wave which occurred July 2021. The influential figure initially dropped to 20% on 09/June/21 before rising and peaking on 10/07/21 at 56% then suddenly dropped back to 37% on 20/07/21. Just like the major waves of December this surge in cases was abruptly interrupted as soon as the influential peaked on 20/07/21. This mini wave has so far been experienced once in London in the last two years. It is also noted that it is relatively rare for influential values to drop down to 20% and below in London based on the NW London archive charts ie approximately once every 5 years. Further occurrences/observations are necessary before this becomes conclusive.
3. Flat “quiet” periods:
The periods between Covid case surges are in general quiet periods with the influential humidity values either flat, dropping below 70% or gradually rising over many months to reach peak values in December.
December sees the introduction of a new phenomenon. Freezing water particles usually visible to the eye in the form of mist, fog etc. These are suspended particles rather than gaseous. These likely cause an impact to indoor dry air activity as they can find their way indoors. Introducing a new dynamic which continues towards March when temperatures start to rise again. Also note there is sometimes a raise in cases leading up to this period. Is it because frozen conditions start to decline and frozen particles of water start to reduce? These are all useful subjects to research and study.
4. Looking ahead
The historical weather charts for London appear consistent with respect to influential values as illustrated above ie when they generally peak in the winter and when they are lowest during the summer months. If this correlation where to be confirmed it suggests we can expect major surges in Covid cases in London at least seasonally in the winter with lowest number of cases during the summer except during a mini Covid wave occurrence mid-year if there is one.
This association also raises another prospect, intriguing questions on whether the apparent vulnerability of SARS-CoV viruses to relative humidity can be exploited to battle the virus? ie using some form of cold humidifier and ventilation system? Several peer reviewed studies suggest this will be beneficial
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