Strategic COVID-19 Pandemic Committee 

Why we should not use a natural herd immunity strategy?

COVID-19 Questions & Myths

Herd immunity (or population immunity) occurs when most of a population is immune to an infectious disease. If there are few susceptible people the infection cannot circulate widely, although infections can still occur. Depending on how contagious an infection is, usually 50% to 90% of a population needs immunity to achieve this (Johns Hopkins Bloomberg School of Public Health). This is usually due to vaccination. Long lasting “natural” herd immunity in a population has not been seen for any disease. 

Dr. Deena Hinshaw notes allowing COVID-19 to infect most of our population is not a wise strategy because:

• The original COVID-19 virus is estimated to be 10 times more deadly than influenza with an estimated mortality rate of 1%. For example, infecting 50% of Albertans (approximately 2.15 million people) would result in 21,500 deaths.

• About 4% of patients overall need hospitalization from the original virus. The new UK and Brazil variants are still to be determined. Our hospital system is usually full and has a total capacity for around 0.2% of the population at any time. Many places have seen health system collapse due to COVID-19 surges with deaths from not being able to provide care for COVID and non COVID patients.

• Some patients describe prolonged illness which resembles Chronic Fatigue Syndrome, so lasting health impacts are a concern.

• Evidence around long-lasting immunity is still unclear. We can’t assume that widespread natural infection will result in herd immunity and we know that vaccines can result in better and longer-term immunity with much less risk than natural infection.

Vaccines train our immune systems to fight disease, similar to being exposed to a disease, but crucially, vaccines work without making us sick. Until we can reach sufficient herd immunity through immunization, the best way to prevent severe illness and death from COVID-19 is to follow public health restrictions.

References:
i. What is Herd Immunity and How Can We Achieve It With COVID-19?, Johns Hopkins Bloomberg School of Public Health
ii. Herd immunity and the Great Barrington Declaration, Alberta Health
iii. Coronavirus disease (COVID-19): Herd immunity, lockdowns and COVID-19, World Health Organization

CLICK ON MORE QUESTIONS TO SEE THE ANSWERS

THIRD WAVE

• The Third Wave is Here. How do I prepare?

PUBLIC HEALTH RESTRICTIONS

• Why is this virus so hard to control? Why do we need these restrictions?

• How do you know when a lockdown strategy is needed?

• Is what we have right now a complete lockdown? What is a circuit breaker strategy?

• The restrictions in Alberta have reduced mortality from COVID-19.

WHY CAN WE NOT RESUME NORMAL LIFE

• I'm 35 years old and not likely to die from COVID-19, so why should I have to follow all these rules?

• Why we can’t live with COVID-19 the same way as with seasonal influenza.

• Why we should not use a natural herd immunity strategy?

• What is Long COVID?

POTENTIAL LOCKDOWN BENEFIT

• The COVID-19 restrictions are saving lives.

• More people have died from COVID-19 than lockdowns.

• Which is worse for the economy, the pandemic or public health restrictions?

• COVID-19 has prevented access to healthcare for non-COVID-19 illnesses and conditions.

• Has the rate of suicides and drug overdoses changed during lockdowns?

• Has the crime rate changed during public health restrictions?