How mortality rates for COVID-19 vary depending on age group

The mayor of Los Angeles, Eric Garcetti, warned the city today that more challenging days were up ahead. He said that residents should expect maybe two more months of restrictions as cases are expected to mount, just as they have mounted in New York City.

In a disturbing development, city officials added that a juvenile had succumbed to complications of what is likely COVID-19 and passed away earlier in the day. Given privacy laws, further details have not been revealed, but it is known that the father, who ‘had close contact on the job daily with the public’, had tested positive for coronavirus. 

 How mortality rates for COVID-19 vary depending on age group

There have been mounting reports of younger people losing their lives, or becoming severely ill, because of the virus. This is particularly upsetting because it challenges the data we have been presented; that young people are unlikely to become seriously unwell and those who are older, over 65 years of age, are at higher risk.

Comprehensive studies by the Chinese CDC, WHO and reports from high-risk countries such as Italy and Spain have reiterated and strengthened these beliefs, but have also added more nuance to our understanding. What are the key revelations so far?

Age is not the only factor

Underlying health conditions also play a role in determining the severity of the infection. Of particular consequence are cardiovascular disease, diabetes, respiratory disease and high blood pressure. Just over 10% of those who have died had CVDs, whereas the figure was a shade over 5% for the other conditions. Those who have more than one pre-existing condition also have a higher mortality rate. 

Chronic conditions hamper the immune response of the body and increase vulnerability to all sorts of ailments and infections. 

Mortality rates are a crude measure and vary by geography

Why is the Italian mortality rate is so much higher than Germany’s? Why does WHO’s measure differ from the Chinese measure? Aside from demographic differences (Italy has an older population; the majority of deaths have been those over 75) and the general health of the population, testing methods vary by country as well. Since milder cases are often not tested, and people recover without any adverse events, these are not included when calculating the mortality rate. So, a country that is currently only testing symptomatic patients or those with more severe conditions is likely to report a higher mortality rate as well. 

Mortality rates by age

For those under 10 years of age, there appear to have been no COVID-19 related deaths. However, this does not mean that infants and young children are completely out of danger. While there have been no deaths, there have been reports of hospitalization and ICU admittances. A widely circulated study published in the journal Paediatrics found that 30% of hospitalizations and ICU visits were in infants below the age of 1. So it does appear that infants may be more vulnerable to the disease than slightly older children. 

For those between 10-20 years of age, the rate of infection and mortality remains low. According to the Chinese CDC study, there is a 0.2% mortality rate in this age group. This confirms what we already suspected: young children and teenagers are not especially vulnerable to the disease - but as evidenced in the LA case, there is still a chance of complications.

For those between 20-29, the mortality rate again hovers at around 0.2%. However, there is a catch - the rate of hospitalization does go up. This means that the disease can develop into something more serious but is still unlikely to progress to a critical phase requiring ventilator support. 

For those between 30-50, the mortality rate rises slightly to around 0.5% and ICU admissions climb to 2%. A linear trend can be clearly seen - as the patients get older, complications increase. 

Those in the age group of 50-69 are considered high risk. Mortality rate jumps to 3.5% in this age group. Hospitalization and ICU visit also shoot up. As mentioned above, this is attributed to a higher likelihood of pre-existing conditions and weakened immune symptoms.

For those over 70, the mortality rate is over 5% and over 10% for those over 80. To maintain perspective, this still means that many elderly people who get COVID-19 will survive, but they are undeniably more vulnerable. 

These percentages also suggest why the world is reacting so seriously to the pandemic - minus containment measures, hospitals will be overwhelmed and there will be a massive loss of human life. While these numbers may make you worry, remember that WHO guidance still remains crucial and effective - wash your hands regularly for 20 seconds, avoid touching your face as much as possible and stay away from those who appear sick.

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