It might depend on how severe the original infection was. A more severe infection might result in a higher level of immunity. A mild infection could lead to a lower level of immunity.
Infected again? It's possible
There have also been a handful of cases where a person has had a second infection after recovering from the first. In some of them, the second infection proved worse than the first.
These cases of reinfection show that people who have had COVID-19 may still be at risk from the virus. That means they still need to adhere to safety guidelines, such as:
- Wearing face masks.
- Staying 6 feet away from others in public.
- Washing hands often.
- Not touching their eyes, nose or mouth with unwashed hands.
What about herd immunity?
Herd immunity occurs when enough people are immune to a virus that it slows the spread through a community. But we're not likely to reach the numbers required for herd immunity through natural infections alone. And doing so could have a high cost in illness and death.
A safer way is to create herd immunity through a vaccine. One good thing about coronaviruses is that they mutate more slowly than many other viruses. Flu viruses, for instance, mutate quickly. That's why we need a new flu shot every year.
But SARS-CoV-2 (the virus that causes COVID-19) appears to change slowly. That gives hope that an effective vaccine could create herd immunity if enough people get it.