What COVID-19 vaccines and medications are available around the world?
Will we need a COVID-19 booster vaccine every year?
COVID-19 booster jabs will now be offered to all over 18s in the UK to help stop a potential wave driven by new variant Omicron. COVID-19 booster vaccines are crucial, giving people longer-term protection against getting seriously ill from the disease. But will we always need periodic boosting against COVID-19, like we do against the flu?
Why we need COVID-19 booster vaccines
After the identification of the new COVID-19 variant Omicron, the gap between the second and third doses has been reduced from six to three months. Additionally, severely immunocompromised are to be offered a fourth dose of a vaccine. The COVID-19 booster jab will either be the Pfizer-BioNTech or Moderna vaccine.
"Boosters stimulate the immune system to raise antibody levels," says William Schaffner, a professor of preventative medicine at Vanderbilt University. "Higher antibody levels generally are associated with a longer duration of protection against serious disease as well as some enhanced protection against variants."
Moderna has announced it is working on combination COVID-19 and seasonal flu vaccines, which would make an annual booster against SARS-CoV-2 more convenient. However, only time will tell if we need a jab every year to protect against COVID-19.
"At this point in time of the evolving timeline with SARS-CoV-2, we truly don't know for sure if we will need annual vaccination for COVID-19 infections as we do for influenza," says Rodney E. Rohde, a professor of clinical laboratory science and an infectious disease specialist at Texas State University. "There are so many unknown variables at the moment that I suspect we will have experts disagreeing on this issue."
There are several reasons why we may need to get a COVID-19 booster vaccine every year.
"The SARS-CoV-2 virus is likely a zoonotic virus (a species of virus that can be transmitted from animals to humans) and we have seen documented evidence of it in a variety of animals. That means it will have an ongoing reservoir to maintain itself alongside ongoing mutation. The CoV family is an RNA family of viruses (a virus which has ribonucleic acid RNA as its genetic material) and many RNA viruses have the unfortunate ability to mutate quickly," explains Rohde.
Several vaccines in common use require boosters. "For example, to maintain protection against tetanus, a booster vaccination is recommended every ten years. Influenza vaccination is required annually because the influenza virus changes frequently."
With COVID-19, Schaffner explains, two things need to be determined. "First, the duration of protection afforded by our current boosters. And secondly, whether the COVID-19 virus will mutate sufficiently to evade protection from the currently available vaccines."
A study looking at the level of protection provided by one of the existing vaccines, the Pfizer BioNTech vaccine, showed increasing risk of becoming infected from three months after administration. Compared with people vaccinated three months or less earlier, the risk of infection was:
- 2.37 times higher for people vaccinated 3-4 months earlier.
- 2.66 times higher for people vaccinated 4-5 months earlier.
- 2.82 times higher for people vaccinated more than five months earlier.
"The issue of 'vaccine escape' mutation is of particular concern because of the appearance of the new Omicron variant," Schaffner says. "Testing is ongoing, but there are early intimations that the Omicron variant may be able to partially thwart the protection of our current vaccines."
Ultimately, we will know more as experts monitor people who have been vaccinated and received a booster, compared to those who did not receive a third vaccine. More information about Omicron will also tell us whether our current vaccination programme is sufficient.
Will the current COVID-19 vaccines have to be altered?
At the moment, it appears that COVID-19 is going to continue to be a rapid mutator. For example, Omicron is the most heavily mutated version of the virus we have seen to date and early evidence suggests it has a higher reinfection risk. However, scientists say it will take about several weeks before it is known how the variant impacts on the effectiveness of vaccines.
"If we do not get the global community vaccinated at a high percentage, we continue to risk giving the virus the opportunity to find unvaccinated populations and drive mutation rates. That may mean we need to occasionally alter our vaccines to keep up with the viral changes," says Rohde.
"However, we may also find that the vaccines continue to protect us. For example, the current data appear to show that many of the existing vaccines have protected us from the Delta variant, at least from the standpoint of high mortality and severe disease that puts people in the hospital."
Again, however, we will have to wait to see whether COVID-19 boosters are required annually. "We must follow the science in real time to answer these questions in the best way. It could also mean that certain geographical regions may need altered vaccines while others may not," says Rohde.
"We also desperately need not only higher acceptance of vaccines and boosters, but also vaccine equity for global protection. Without vaccine equity, we will have major pockets of unprotected populations which allows ongoing virus mutations."
Who can get a COVID-19 booster vaccine?
All over-18s are to be offered the booster jab, after the Joint Committee on Vaccination and Immunisation (JCVI) announced that the waiting time was being cut for all adults. Priority for booking will be decided by the NHS and the rollout will be staggered by age group, with older people invited for boosters first.
In response to the Omicron variant, the government has also announced new rules on self-isolation and that face masks will be compulsory in shops and on public transport in England.