Why Do Countries COVID-19 Death Rates Vary So Much?

European countries have the highest infection and death rates, while Asian countries have considerably lower rates, and Canada falls between Asia and the U.S.

Infected people in the U.S. are 500 times more likely to die in comparison with Singapore; the data is too serious to be ignored.

Death rates as on 8^th May: World: 6.9%; Europe: 9.6%; North America: 6 %; Asia 3.4%; South America: 5.1%; Africa: 3.8%; Oceania: 1.4% and deaths per Million Population: USA: 232; Spain: 558; World: 34; India: 2

On 15^th may: Case fatality: USA 6%; Switzerland 6%; Sweden 12.4%; Belgium 16.3%; Spain 11.8%; France 15%; Germany 4.4%; Italy 13.9%; Netherland 12.8%; Canada 6.9%; UK 14.7%; Hong Kong 0.4%; Singapore 0.1%; South Korea 2.4%; Taiwan 1.4%; China 5.6% and Japan 3.8%.

What really explains these stark differences?

Multiple factors are at play: testing capacity, case definitions, age distribution, preparedness

1. The extent of testing:Since the outbreak in January this year, testing has been widely available in Asia. Germany, the country with the lowest mortality rate, also initiated early testing. A lack of testing would lead to underestimation of cases and deaths, but countries that have been better able to control the outbreak ensured wide access to testing. It does not appear that extensive testing makes the epidemic look worse by finding more people with minor or no symptoms. Infection rates are low in Asian countries and high in the U.S. and Spain where testing was less available. However, in India with testing only of symptomatic and high-risk cases, the case fatality remains < 3.5%.
2. Countries define and report COVID-19-related deaths differently, and the methods have changed over time. In the early phases of the epidemic in China, the initial few versions of case definition stated that up to six criteria needed to be fulfilled, which possibly led to an underestimation of cases by five-fold. As of April 14, 2020, the new CDC guidelines include counting both confirmed and probable cases, depending on doctors judgment based on symptoms and contact history. Additionally, attributing cause of death to COVID-19 seems to vary by country, especially since most of these deaths occur in people with chronic illnesses. Some countries are not including deaths due to MI, embolism, etc., as COVID deaths.  However, this can make a difference of only 5% as evident by cases on 12 Febraury when China included the clinical CT diagnosed criteria.
3. Demographics: In Hong Kong, 60% of cases were attributed to incoming travelers, primarily constituting returning students and expatriates. In Singapore, outbreaks in foreign worker dormitories amount to 80% of cases, while community cases only account for 10%. These younger populations are relatively healthy and may contribute to overall lower mortality rates. In European countries such as France and Italy, and in the U.S., community outbreaks in nursing homes and long-term care facilities have contributed to higher infection and mortality rates among the elderly. It does not explain; however, why in Japan with very high elderly population, the morality remains 3.8%.
4. Density of population: India: In states with average population density of 1185/sq km, the average number of cases were 2048. On the contrary, in states with population density of 909/sq km, the number of cases were 56. When Chandigarh and Pondicherry were taken out from this group, the Average Density of other states were 217 and the average number of cases were 35. [HCFI]
5. BCG vaccination: Countries that do not have a BCG vaccination policy in place seem to have ten times greater incidence of and mortality from COVID-19, compared to the countries that have the policy in place, as per a forthcoming study from medical researchers in the US and UK, analyzing data from 178 countries. The study assessed COVID-19 instances and mortality for 15 days from 9 to 24 March across 178 countries and concluded that the incidence of COVID-19 was 38.4 per million in countries with BCG vaccination compared to 358.4 per million in countries without such a program. The death rate was 4.28/million in countries with BCG programs compared to 40/million in countries without such a program. Among the 178 countries studied, 21 had no vaccination program, while the status was unclear in 26 countries. 
6. A report titled “MMR Vaccine Appears to Confer Strong Protection from COVID-19: Few Deaths from SARS-CoV-2 in Highly Vaccinated Populations”has underscored how children and most adults below 50 are likely protected from COVID-19 because of the rubella component of common MMR vaccinations. Some young children with a rare condition - Kawasaki disease - are; however, facing severe COVID-19 complications which could be related to a relationship between MMR vaccines and COVID-19.

There is a large amount of data suggesting that the rubella component of MMR vaccines protects most children from COVID-19. However, if a child has a genetic predisposition to Kawasaki disease, they may not be protected since Kawasaki disease is known to decrease the responsiveness of MMR vaccinations.

7. Countries also differ in the capacity of their healthcare systems to handle a rapidly spreading epidemic.When a spike in the number of patients overwhelms the healthcare systems capacity, mortality rates are bound to shoot up. Countries with best of the ICU care will have lower mortality rates. But as on today, there are only 2% of the patients who are serious, and this would only make 0.3% difference in the case fatality rate. And also, the case fatality in Europe and North America with very high level of intensive care is the highest.
8. Robust preparedness and response strategies: Death rates were lower in countries and regions with standing plans for containing the infection. For instance, Singapore, Hong Kong, China, and Canada had fought the Severe Acute Respiratory Syndrome (SARS) epidemic in 2003. That led them to develop national strategies to build capacity, preparedness, coordination, and communication in preparation for the next outbreak. The SARS experience also gave way to a higher level of public acceptance and adherence to masking and social distancing measures. Amongst CMAAO countries, India has done worse as it had never faced SARS-like illness before.
9. Negative isolation rooms and timely RT PCR report: A negative-pressure AII room is meant to isolate a patient who is suspected of, or has been diagnosed with, an airborne infectious disease. The aim is to help prevent the spread of a disease from an infected patient to others in the hospital.

Negative-pressure isolation rooms should have minimum 12 air changes of exhaust per hour and must maintain a minimum 0.01-inch WC negative-pressure differential to the adjacent corridor, irrespective of the usage of an anteroom. A setpoint close to minus 0.03-inch WC is employed. When an infectious patient is not there, the room may be occupied by non-infectious patients. The negative-pressure relationship to the corridor must be upheld; however, it is not necessary to be maintained at the minimum of minus 0.01-inch WC.   

All SARS and MERS affected countries had enough and mandatory AII rooms in their hospitals. All the patients in the triage room are in kept in the ER AII room. The RT PCR report is available in three hours and then the patient is shifted to a COVID or NON COVID facility accordingly. South Korea this time expanded their AII room numbers in five days.

10. Culture:Most Asian countries - Japan, India, China, South Korea, etc. - have a culture of Namaste or bowing. This might have been the protective factor in human to human transmission. The burka, nakab wearing in Islam may be protective in Arabian countries. In cult communities, the mortality and number of cases would have been half if the cultural practices of South Korean Church and JAMATIS in India would have cooperated in the virus spreading management. These communities do not believe in masking, isolation and treatment. Also, culture of not putting elderly in the nursing homes in the Asian countries has also helped. In US and Europe, nursing home inhabitants had high mortality rates.
11. The virus behaves in seven different ways and these responses may differ from country to country with variable mortalities.
12. It’s a viral self-limiting disease
13. It caused immune inflammation (high ESR, CRP and ferritin)
14. It causes bacteria like activity (responds to antibiotics and severe cases have high procalcitonin levels)
15. It causes thrombi inflammation (high D Dimer with high fibrinogen levels).
16. It causes cytokine storm like influenza.
17. It has HIV like activity, attacks CD4 and T cells and causes low lymphocytes counts.
18. Walking dead: with severe silent hypoxia without damage to the lungs and retained consciousness levels. 

For example, severe inflammatory disease among infants who are arriving in hospital with high fevers and swollen arteries.

(Excerpts from: Medpage Today; Economic Times; GlobeNewswire)

Total cases and deaths across the world 

Dr KK Aggarwal

 President CMAAO, HCFI, Past National President IMA, Chief Editor Medtalks