Blame it on the highly infectious Delta variant. Recently published new data suggests that three doses of the Pfizer-BioNTech vaccine provided four times as much protection against Covid-19 infection as two doses in people 60 years and older.
Some experts are subsequently recommending a third dose of the Covid-19 vaccine for some people, but there is much confusion – and debate – around administering third doses and booster shots to the general population.
A third dose is now recommended in the United States for individuals who are moderately to severely immunocompromised,” explains Limpopo general practitioner, Dr Vusi Khosa.
Khosa says, “It’s not a matter of vaccines not working but a mere strengthening layer for you to stand a better chance of avoiding severe complications in the event you contract the virus.”
Viruses are always evolving and booster shots are also said to be necessary to ensure the durability of vaccines, to prevent unabated transmission, and subsequently to protect against the development of future variants.
New shots spark debate
The third dose can be administered 28 days after a person’s second dose. Its rollout has sparked an ethical and political debate, however, since large numbers of the global population have not yet received their initial vaccines.
Some experts, including the World Health Organization (WHO) are advocating for vaccines to be made available more widely first.
Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota in Minneapolis, says curbing the spread of Covid-19 is key to preventing the emergence of variants even more dangerous than Delta, he said.
“It’s a worldwide epidemic that will continue until you take care of it around the world.
“From a humanitarian standpoint, this is obviously critical,” he said.
Who may well need an additional booster?
According to the United States Centre for Disease Control and Prevention (CDC), Covid-19 vaccines have been effective in preventing hospitalisations, deaths and severe illness.
Dr Rochelle Walensky, director of the US CDC, recently approved the Advisory Committee on Immunisation Practices’ recommendation on who should receive an additional or third dose of Covid-19 vaccine.
Healthcare workers and other vulnerable groups in the US may start getting booster shots of the Pfizer or Moderna vaccine as early as September.
“The additional dose aims to target people with compromised immune systems, such as cancer patients, transplant recipients, HIV patients and immunosuppressant drug users, as well as [people with] a variety of other conditions that similarly left vaccinated people with less immunity than expected,” Walensky said in a statement.
Let’s get some FAQs straight:
What’s the difference between a booster dose and an additional dose?
People who are moderately to severely immunocompromised do not build enough (or any) protection when they first get a vaccination. When this happens, getting another dose of the vaccine can sometimes help them build more protection against the disease.
This appears to be the case for some immunocompromised people and Covid-19 vaccines.
The CDC recommends moderately to severely immunocompromised people consider receiving an additional (third) dose of an mRNA Covid-19 vaccine at least 28 days after the completion of the initial 2-dose mRNA Covid-19 vaccine series.
In contrast, a “booster dose” refers to another dose of vaccine that is given to someone who built enough protection after vaccination, but whose protection decreased over time (this is called waning immunity).
Who will be the first people to get a booster dose?
The CDC explains that the goal was for the first people eligible for a booster dose to be those who were the first to receive a Covid-19 vaccination (those who are most at risk). These include healthcare providers, residents of long-term care facilities and other older adults.
If we need a booster dose, does that mean the vaccines aren’t working?
No. Covid-19 vaccines prevent severe illness, hospitalisation and death, even against the widely circulating Delta variant. However, with the Delta variant, public health experts are starting to see reduced protection against mild and moderate disease.
Neither third nor booster doses are currently available or recommended in South Africa.