# COVID-19/All-cause deaths/Infectious Diseases

Death Cases are very late indicators for epidemiological responses. The main objective of responses are to
* prevent death,
* prevent hospitalization,
* prevent people from getting infected.
In the chain of logic preventing people from getting infected is logically the first step. Less infected people reduce the number of people that must be treated in hospital. The number of hospitalizations is an indicator of severe cases that might die. We must distinguish between a health system that operational beyond its capacity and a health system that does not have the capacity to treat all patients, that need the medical support. The fraction of people that will die increase if they will not get the need treatment, when they need it.

## Learning Task

Analyze the available risk mitigation strategies and its impact on the reduction of infections.

## Death Cases and COVID-19

This part of the learning resource will look into death numbers and risk mitigation strategies. The preparedness plans of public health agencies, health care facilities, ... are more complex. Please follow and analyze peer reviewed public health journals on that topic and the recommendations of the public health system that must be updated according to new scientific knowledge in virology, medical treatments, .... This learning resource is a wiki, can be outdated, incomplete, ... .

### Death Counts in early Phase

COVID-19 was new virus, when cases and death are described by medical staff for the first time. Tests were not available at that time. Medical staff or the public health system just observe epidemiological patterns of a contact induced disease (infections). E.g. people that were not sick before show all of the sudden with the same symptoms of the patient that they visited 2 weeks before and pop up in the same hospital. At that time medical decision making introduces protective measures to prevent other patients to be infected (percautionary principle).

### Early Observations and Mortality

For a new virus the available tests for other viruses are unappropriate and a test must be designed and scientifically analyzed. This takes time Nevertheless if the health systems observes mortality in conjunction with an unclassified disease that seems spreads within among humans, then preventive measures for other patients are introduced to prevent the virus from spreading, even if the public health system and virology cannot classify the disease at that time. The containment strategy tries to keep number of infections low, to avoid other epidemiological interventions like lockdowns, that have more sideeffects on society, economy, .... All-cause deaths will not be helpful in this early phase because the number of death cannot help contact tracing.

### Classification of a new Virus and Mortality

Risk mitigation of the public health system looks (among many other tasks) at "who had contact with identified new infections" (contact tracing). This Virology at the same time has the task to identify the genectic oode of the new virus (COVID-19) and classify the genetic code. The classification is necessary to estimate if the virus is high pathogenic (e.g. if a virus is classified as H1N1 virus, H5N1, ... . The classification is important especially for a new virus, because assessment of the risk is associated with genetic simularity to other known viruses. The challenging part is not the sequencing of the genetic code. The challenging part is the scientific analysis which part of the genetic code for "behaviour" of virus in the host. If early containment of the virus is the key, all-cause death or even the COVID-19 positive deaths will not be helpful for risk assessment. Nevertheless mortality is observed by public health agencies during the decision making process. The classification of the virus has uncertaintities. The similarities to other known viruses do not excluded the possibility that is more harmful or less harmful. The assessement includes if the virus is high pathogenic and/or high infectious. Similarities of virus can help in the early phase and all-cause death cannot help for the assessment. Furthermore ethical consideration must be respected. Waiting until all-cause death show a signicant signal of a pandemic, is again (a too) late indicator for implementation risk mitigation strategies. Nevertheless it is important retrospectively to look on all-cause death and other death causes to see what was the impact of COVID-19 on other causes of death.

### Genetic Code and Evolution

Viruses can change their genetic code over time (e.g. create new subtypes). If the genetic code of the virus changes, also immunisation might fail. For some diseases the vaccination will be preventive for a long period of time. E.g. for influenza viruses the vaccination must be adapted from year to year. So the preventive measure must be adapted from year to year. It is the objective to prevent an epidemiological spread of a disease in the early phase, because new viruses spread with an exponential growth in the beginning, because a limiting factor for the growth like immunity of the population or vaccination is not there (see basic introduction to SIR-Model).