It sounded ideal: Two shots of a vaccine, which all but removes the risk of dying of Covid-19, letting us go back to normal.
It might not be that easy.
Immunity to a virus, whether generated through a vaccine or by being infected, usually doesn’t last forever. Over time, antibody levels can wane.
This is why we might need a booster shot after a vaccination injection and is one of the reasons why we need a new flu vaccine every year. For seasonal coronaviruses, immunity typically lasts for less than a year.
We still don’t know how long immunity to Covid-19 lasts. The only way to know is to wait and see.
We've had Covid-19 vaccines available for about seven months, and the evidence suggests immunity levels are still high for vaccinated people. The results are so promising it's even possible that immunity could last forever.
If that holds true, ka pai. We’ll be okay for a while.
If it doesn’t, it might mean that two shots is not enough. We may need a booster shot, or even regular, annual vaccinations to protect against the virus, much like the seasonal flu.
One of the biggest concerns will be the rise of new variants. Another reason we need a flu vaccine every year is because the influenza virus constantly mutates. The influenza viruses one year will be different strains to previous ones - this is why you sometimes have bad flu seasons, and not so bad flu seasons.
We know the SARS-CoV-2 coronavirus that causes Covid-19 changes and mutates, producing different variants of the virus. The Delta variant, for example, is more transmissible than earlier strains.
Evidence shows current Covid-19 vaccines are effective against the Delta variant. But the more the virus circulates, the more likely it is that new variants will sidestep the vaccine. In those cases, a new vaccine may be needed to deal with a new variant.
This is why widespread vaccination is so important: Not getting vaccinated affects everyone.
Even if you’re not concerned about your own personal health, allowing the virus to infect you raises the risk of new strains that can infect those others who have been vaccinated, including our vulnerable and at-risk whānau.
It is likely Covid-19 booster shots will be approved, whatever the case. Israel is already rolling out third shots for people with compromised immunity. Early data suggests a third vaccine dose can increase antibody levels in organ transplant recipients, better protecting them from the virus.
For now, the future of the Covid-19 vaccine is up in the air. What we do know is that high vaccination coverage now would help reduce the likelihood of new strains, and thus the need for more vaccinations and vaccines down the line.
Reporting disclosure statement: This post was reviewed by The Whole Truth: Covid-19 Vaccination expert panel member, Dr Dianne Sika-Paotonu, a senior lecturer in pathology and molecular medicine.
