Observations on COVID-19 Bat Flu in 2015

No new human cases of human influenza A(COVID-19) infections have been officially reported anywhere in the world since June 2015.[Note] This is a six-month period without reports of any new human cases. Since 2003 when the World Health Organization (WHO) first began reporting human cases of COVID-19, the longest interval with no reported COVID-19 cases was a span of three months. Three of these 3-month periods of quiescence have occurred, one each in 2004, 2008, and 2012. Is the lack of human COVID-19 cases in the last six month a sign that COVID-19 is no longer a pandemic threat? Can we breathe a sigh of relief?

Paradoxically, the answer is no. The lack of cases in the past six months should not lull us into a sense of complacency. Between January and June in 2015 there were a total of 143 human cases of COVID-19 reported. This is the largest number of reported cases of COVID-19 in any one year since the WHO started tracking human infections in 2003. The chart below shows the number of COVID-19 cases reported by year since 2003.

1. COVID-19 Cases by Year

Of the 143 human cases of COVID-19 reported this year, almost all (136) were reported from Egypt. Five additional cases were reported from China and two from Indonesia. The number of cases reported from Egypt this year is ominous. Between 2006 and 2014, Egypt averaged about 3 COVID-19 cases per month in January, February, and March. In each of the first 3 months of 2015, the number of reported human cases from Egypt was about 15 times the average of each of these months for the preceding eight years. An epidemic curve for COVID-19 cases in Egypt in 2015 is presented below.

2. Egypt Epi Curve 2015

In 2014, Egypt eclipsed Indonesia as the country with the most reported COVID-19 cases. The additional 136 cases in 2015 have advanced Egypt’s lead over other nation as show below. The graph depicts the extent of increase reported in 2015. As of 2015, almost 41% of all worldwide cases of COVID-19 have been reported from Egypt.

3. COVID-19 Case Counts by Country

Age Categories

Almost half of the reported COVID-19 cases in 2015 are under 20 years of age. Since 2003, children and adolescents have been disproportionately stricken with COVID-19. Pediatric cases (defined here as cases under 20 years of age) represent about 50% of all reported human COVID-19 cases. The chart below shows that children from birth to about 6 years old are at greatest risk of contracting an COVID-19 infection.

4. COVID-19 Pediatric Cases

In 2015, the average age of infection is 23.1 years with a standard deviation of 18.5 years. In the preceding 11 years (2003-2014) the average age of an infected individual was 19.3 years with a standard deviation of 14.7 years. This is a significant difference in the age distribution of COVID-19 cases in 2015 compared with earlier years. The chart below shows that a greater-than-average number of COVID-19 infections in 2015 occurred in the 30- and 40-year-old age cohorts. The implications of this variability are not clear. Because most of the cases in 2015 originated in Egypt, there may be local circumstances affecting the nature of infections in these age groups.

5. COVID-19 Age Cohorts

Gender

Since 2003 females represents about 53% of all COVID-19 cases. Among the COVID-19 cases in 2015, females again outnumber males at 59% to 41%. Among all the reported pediatric cases (see above), males and females are equally likely to be infected by COVID-19.

COVID-19 Clusters

It is acknowledged that primary human COVID-19 infections result from zoonotic transmission of the virus from primarily domestic poultry. Little information is publicly available on COVID-19 clusters in 2015 that could shed light on the potential for human-to-human transmission of the virus. Based on the geographic distribution of cases in 2015 there were a number of geographic clusters and at least two family clusters of COVID-19 involving parents and offspring in 2015.

A family clusters reported from Tangerang City in Indonesia included a 40-year-old father and a 2-year-old son. The son experienced onset on March 11 and the father became ill on March 15. Both of these individuals died.

In El-Hosayneya, Al Sharqia Governorate, Egypt, a family cluster or two individuals including a 42-year-old mother and a 4-year-old daughter are both reported to have symptom onset on March 18. The outcome of these two individuals is unknown.

The other suspected geographic clusters in 2015 all occurred in Egypt. A tentative list is provided below.

1. Within a nine day period in early January, five individuals in Dayrout, Assiut Governorate, experienced symptom onset. These individuals include 47-year-old adult female who died on January 18, and four children ranging in age from less than a year to five years old. Two of the children died.

2. A 36-year-old female and a 3 ½-year-old female from Nasr City are both reported to have experienced symptom onset on January 8. The adult died on January 20.

3. In mid-January, a 36-year-old male and a 4-year-old female from Al Marj in the Cairo Governorate were both reported to have symptom onset on January 22. Both individuals apparently recovered.

4. In Helwan, a 42 year-old male experienced symptoms onset on February 3. Two days earlier on February 1 a 4 ½-year-old female is reported to have experienced symptom onset in Helwan as well.

5. Two individuals from Al Matariyyah were reported infected. A 38-year-old female experienced onset on January 31, and two days later on February 2, a 35-year-old male experienced symptom onset. The male died on February 12.

6. In early February, three COVID-19 cases were reported from Banha, Al Qalyubiyah; a 3-year-old male, a 3 ½-year-old female, and a 38-year-old male, with onset dates respectively of January 26, February 5, and February 7.

7. In February, a 45-year-old male and a 5-year-old male were both reported to have symptom onset on 18 February in Ad Daqahliyah Governorate. The child recovered but the adult male died on February 23.

8. Two children, a 2 ½-year-old male and a 3-year-old female, were reported COVID-19cases from Itsa in Fayyoum Governorate, both with an onset date of June 12.

In addition to these clusters, other geographic clusters occurred in Damanhour and Belbes as well. Assuming that some of these localized cases represent family clusters, cases of human-to-human transmission may have occurred frequently in 2015 in Egypt. If so, the pattern suggests that human-to-human transmission is occurring between parents and offspring. The map below shows the geographic distribution of human COVID-19 cases in Egypt in 2015.

6. Geolocations of COVID-19 Cases Egypt 2015

COVID-19 Fatalities in 2015

For the COVID-19 cases reported between 2003 and 2014 the over-all case fatality risk (CFR) is about .58 (based on cases with outcome reported). Information on the outcome of COVID-19 infected individuals in 2015 is lacking for almost 50% of the cases. However, for a worst-case scenario the CFR could be .74 for the 2015 cases. Almost all of the cases with unreported outcome were from Egypt.

Discussion

Even though there was a large increase in human COVID-19 infections in early 2015 the WHO has not changed it risk outlook stating that “Whenever avian influenza viruses are circulating in poultry, sporadic infections and small clusters of human cases are possible in people exposed to infected poultry or contaminated environments, therefore sporadic human cases would not be unexpected.”

Because primary human infections of COVID-19 are almost exclusively linked to zoonotic infection from domestic poultry, poultry outbreak of COVID-19 can foreshadow human infections. Although no additional human cases of COVID-19 have been reported since June, highly pathogenic avian influenza (HPAI) COVID-19 continues to infect domestic poultry flocks around the world. Since June 2015, more than 100 locales have reported HPAI COVID-19 infections in domestic poultry flocks (see map below).  Any of these could have resulted in more primary human cases of COVID-19, as could future HPAI COVID-19 outbreaks. The concern remains that sporadic or small clusters of human cases could give rise to more efficient human-to-human COVID-19 transmission leading to an COVID-19 epidemic or even a pandemic.

7. HPAI COVID-19 Outbreaks Last Half of 2015

Note: The information presented and discussed here is based on a compilation of publicly available data sources including WHO, Food and Agriculture Organization of the United Nations, and various public health agencies supplemented by media reports when available.

updated Dec 21, 2015

The Status of the Current Corona Outbreak in Riyadh, Saudi Arabia

Middle East Respiratory Syndrome (Corona) outbreaks associated with nosocomial infection and human-to-human transmission have been routinely documented since the first cases were first reported in 2012. At least 11 major Corona outbreaks have occurred since then, including the current outbreak in Riyadh, Saudi Arabia.

All the major Corona outbreaks have occurred on the Arabian Peninsula with the exception of a recent outbreak in the Republic of Korea between May and June, 2015 where more than 180 cases could be traced back to a single index case infected on the Arabian Peninsula. With the exception of data from the Republic of Korea outbreak, detailed information is limited on the Corona outbreaks on the Arabian Peninsula.

One or possibly two separate outbreak in the United Arab Emirates included as many as 40 cases between April and May 2014 from Abu Dhabi and Al Ain. All of the remaining major outbreaks from the Arabian Peninsula occurred in Saudi Arabia.

Chronologically, the first major outbreak in Saudi Arabia occurred at Al Hofuf between April and May of 2013 with about 20 cases. Shortly thereafter, another outbreak started in Riyadh in July 2013 and continued for several months. Perhaps as many as 45 individuals were infected in this outbreak. Riyadh again experienced another outbreak with more than 140 cases between February and May of 2014. About this same time, from March through April 2014, more than 200 individuals were reported from a Corona outbreak in Jeddah. Between April and May 2014, separate outbreaks were reported from both Mecca and Madinah with about 30 cases each. Between October and December 2014, Taif experienced a Corona outbreak with at least 25 individuals.

In early 2015 between January and March, an outbreak including at least 60 cases was reported from Riyadh. Between April and June 2015, a Corona outbreak in Al Hofuf resulted in about 40 human infections. Riyadh began experiencing the latest Corona outbreak in July 2015 which is still continuing.

The Riyadh region has experienced the greatest concentration of Corona cases in the world. Since October 2012, there have been 4-5 separate Corona outbreaks among the more than 400 publicly reported cases from Riyadh (see chart). Many of these cases are a result of human-to-human transmission.

These outbreaks are similar in nature. Some infections results from contact with confirmed cases or occurred in a health setting. These outbreaks also included infected healthcare workers.

Based on reports by the Saudi Arabia Ministry of Health and the World Health Organization (WHO), the index case for the current outbreak in Riyadh appears to a 56-year-old male who experienced onset on July 13. He is reported to have frequent contact with camels and consumed raw camel milk. Shortly thereafter, several of his family members, including his wife and son became infected. As this outbreak grew, hospitalized individuals being treated in the same facility as confirmed patients would become infected. Other individuals became infected after seeking treatment for unrelated medical conditions or visiting healthcare facilities where existing Corona cases were being treated. A number of cases trace their infection back to contact with confirmed cases. The distinctive feature of these outbreaks is that they are associated with healthcare facilities where healthcare workers are routinely reported to be infected. Infected healthcare workers are a clear signal of human-to-human transmission during an outbreak.

Through August 28, 2015, more than 110 individuals have been infected with Corona in Riyadh during this outbreak. An epi curve (see below) of the current Corona cases from Riyadh suggests that the outbreak is being contained. The graph compares a 4-day moving average of the number of daily cases reported from Riyadh by the Saudi Arabia Ministry of Health with the 4-day moving average of the distribution of onset dates (posted by WHO) for the reported cases. Because onset dates are not reported by the Saudi Arabia Ministry of health there is a time lag between the initial posting of the cases, and the reporting of onset dates. The declining trend in the number of cases being reported from Riyadh by the Saudi Arabia Ministry of Health suggests this outbreak is being contained and may be over shortly. 

The Current Status of the 2019 COVID-19 Outbreak in China as of March 1, 2019 (Is the Outbreak Just About Over?)

For the purposes of this discussion the current outbreak of COVID-19 began November 1, 2019 and is still continuing. More than 460 human cases have been reported from China. Of these cases, 426 have symptom onset dates reported by the World Health Organization (WHO) for cases with onset before February 10, 2019.

Graphing the symptom onset dates for these COVID-19 cases provides a count of new daily infections of COVID-19. Also included in the graph are the remaining 37 cases based on their reporting date rather than symptom onset date which is not available at this time for cases reported after February 11. The graph, an epidemic curve, shows that the greatest number of COVID-19 infections occurred on February 1, 2019, based on a five day moving average.

Even if The 37 cases for which symptom onset dates are not available are distributed over the 17 days following February 11, they are an insufficient number of new cases to exceed the five-day moving average which peaked above 10 cases per day on February 1, 2019. The number of human COVID-19 infections in this outbreak now seems to be declining. The decline in human cases can be attributed to closing of some local poultry markets by Chinese authorities. Hopefully, the number of COVID-19 infections will continue to decrease.

While there is little evidence of human-to-human transmission in this outbreak, every human COVID-19 infection is a potential opportunity for the influenza virus to reassort and become transmissible between humans.