When should I get my Covid 19 booster?

When is the "best time"? I asked the experts.

Last week, I got my Covid 19 vaccine booster. It’s my fifth vaccine - I’ve had two primary doses, two boosters and I just got my Pfizer BA.4/5 bivalent vaccine. I’ve possibly had one more than y’all because I’m a caregiver. Caregivers were at one point able to get a booster earlier than others.

Boosters provide an extra layer of protection to your previous vaccination and keep your immunity levels high. They’re not available to everyone.

If you are 30 years of age and over, you can have a booster regardless of the number of boosters you have already had.

You can have a booster if, you have had your first two Covid 19 vaccinations (your primary course), you had Covid 19 at least six months ago, and you haven’t had another Covid 19 vaccine in at least six months. You can have your Covid booster at the same time as your flu vaccine.

Boosters are especially recommended for, all people over 65 years old, Māori and Pacific people aged 50 and over, pregnant people with health conditions that put them at higher risk of severe illness from Covid 19, people with disability with significant or complex health needs, and people with serious mental health conditions.

Some people aged 16 to 29 can have an additional booster dose. This includes severely immunocompromised people, pregnant people, those who have a medical condition that increases the risk of severe illness from Covid 19, those who live with disability with significant or complex health needs or multiple comorbidities. 

Young people aged 12 to 15 who have a medical condition that increases the risk of severe illness from Covid 19 can talk to their GP, nurse or healthcare provider about whether they should have a booster and how to get a prescription.

Photo by Adam Gethin

I had Covid 19 for the first time at Christmas after travelling. So it’s definitely time for me to get boosted. Still, my husband and I have had some conversations about when the “best” time to boost is.

I thought I’d ask the experts. I sent them two questions:

Is there a best time to get your Covid 19 booster? If so, when. If there isn't - why? And, why should you still get your booster even if you've already had Covid 19?

When’s the best time to get boosted?

Professor Michael Plank, Te Pūnaha Matatini and University of Canterbury: “The best time to get your Covid booster is as soon as you become eligible! That means six months after your most recent Covid vaccination or Covid infection. If you are eligible, now is a good time so you have maximum protection for the winter respiratory illness season.”

“It's a good idea to get a booster even if you've had Covid before because immunity wanes over time and it's common to catch Covid again. Getting a booster will top up your immunity and maximise your chances of fighting the virus off or having a relatively mild case.”"

Emily: Hypothetically, if someone was going to a big concert or show, in October, should they delay their booster?

“It might make some sense to try and maximise your immunity for when you have an important event. But on the other hand October is barely three months away and the strongest immunity lasts three to six months after a vaccine so now is a good time.” 

Dr David Welch, University of Auckland: “Is there a best time? There is a trade-off in when to get a booster between not wanting to waste time, money and effort by having too many shots and not going long periods with low levels of protection against Covid 19 by having too few shots. Official advice for the fourth shot is that it should be six months since the last infection or booster which for most people probably strikes a decent balance. A much shorter gap and you'd already have decent immunity, [wait] longer and immunity - especially vaccine induced - is beginning to wane significantly.”

“Another thing that might be worth taking into account is the level of risk you are likely to see in the near future, and trying to time maximum immunity from a booster with the times of high risk. For example, if you are not in indoor environments much for the next few months but then expect to travel and spend lots of time in crowded rooms, you could hold off getting the booster until a month or so before the travel starts [when] you will be entering high risk environments with peak immunity.”

“…it is sensible from a population point of view to time booster shots so that people at elevated risk of hospitalisation from Covid have high immunity during the winter flu season when hospitals are full from other diseases. Really, that is sensible from a individual point of view too - you don't want to be needing a hospital when everyone else is.”

“Why get a booster when you have already had Covid? Because immunity wanes over time, and getting the vaccine helps restore immunity and reduce the chance of serious sickness if you do get infected.”

Joan Ingram, Medical Advisor, The Immunisation Advisory Centre: “The main benefit of vaccination is to reduce the risk of severe Covid 19 infection including hospitalisation and death. Booster doses have the greatest additional benefit in those who have a higher risk of severe disease ‑ older people, those with other health conditions especially immunocompromised, Māori and Pacific peoples and those living with deprivation.  It is very complicated when to advise a booster as someone’s current protection is probably influenced by both cumulative number of vaccine doses, number of times infected, and timing of most recent vaccination or infection, and how closely the circulating variant matches the vaccine or prior infection. The best time may thus vary.

“As a guideline if it is more than six months since a dose of vaccine or infection another dose will improve protection. Some may wish to have a dose prior to travel for that brief protection against infection.”

“We know protection against severe disease declines with time with good protection against severe disease declining after about six months from a previous dose.  It is thus sensible to have a booster dose to lift falling antibody levels after at least six months especially if you have a risk for severe Covid 19 infection.  We may end up recommending an annual booster dose.”

Associate Professor Helen Petousis-Harris, Vaccinologist, University of Auckland: “The value of a second (or third…) booster depends on your age and general health. There is clear value in keeping boosted for the elderly and people who have significant immune compromise conditions [which is] currently six months after last exposure.”

“The main reason is because the antibody that prevents infection or mild infection wanes, coupled with the constant evolution of the virus and emergence of new variants that can evade these antibodies.”

“However, the long-term immune memory does two things these antibodies do not. One is that the memory and t-cells recognise the variants and the other is that they kick into action in time to prevent severe disease.”

“For the older [and] frailer among us, even a mild infection can be serious so the more transient antibody is more important.”

“Most studies now compare the difference in risk between single booster and 2 boosters and see modest to moderate advantages. When you compare boosted with never vaccinated the difference is huge.”

“The best immunity comes from a combination of infection and vaccine. Boosters do appear to reduce risk for Omicron-related long-Covid.”

Thank you to the nice scientists and doctors and professors who answered me. If you don’t think Covid 19 is real and you think vaccines are the devil please send all replies to: Idontcare@truly.com. If you have burning questions you’d like me to look into, become a paid subscriber and let me know via email or comment. Answers were edited for length and to fit the EWW style guide - which I make up each day, but today means Covid has a capital C and no dash before the 19. You can book your booster here.