Should You Get Your 2nd COVID-19 Vaccine Booster Now, Or Wait Until Fall?

You may be debating whether to obtain the second Covid-19 booster now or wait until the fall. That could be because the booster part two messaging has been a bit hazy.

“Boosters are safe, and adults over 50 can now obtain one further booster 4 months after their first dosage to strengthen their protection,” said Rochelle P. Walensky, MD, in a CDC press release on March 29. But “can” isn't always “should.” For example, you can probably eat five hot dogs at once. Also, novel Covid-19 vaccines, such as ones targeting Omicron variations, may be released this summer. So, what should you do about the second booster shot?

First, look at your age, as the FDA approved second booster doses of either the Pfizer or Moderna Covid-19 vaccinations for those aged 50 and older in late March. That implies if you are 49 years and 364 days old or younger, you can skip the second booster for another day. The FDA approved the second booster for those who are younger (at least 12 years old for the Pfizer Covid-19 booster and 18 years old for the Moderna booster) and have a weaker immune system.

In all situations, wait at least four months after your first booster dose before taking your second. This may help your immune system respond better to the second booster. With things constantly evolving, though, it may be worth holding off on that second Covid-19 booster for a bit unless you fall into one of the FDA's two key categories.

However, if you are eligible for Booster Act 2, there are some strong reasons to do so. Most critically, this pandemic is not over — SARS-CoV-2 is still spreading. In fact, recent increases in Covid-19 cases across the US have prompted fears of yet another Covid-19 outbreak. Yet, many people "don’t want to be inconvenienced," and they are ditching Covid-19 precautions such as face masks as if they bite. Many people claim to be “careful,” but that word means many, many different things to different people.

On top of that, immunity gained from previous vaccine doses or residuals from illness may be wearing off. That means many people may find themselves unexpectedly and unintentionally exposed during this next uptick/possible surge of the latest virus variant. This is especially relevant if you have a higher risk of infection or Covid-19 complications.

Getting another booster isn't extremely hazardous either. There is no evidence that the second booster has more side effects than the first booster or the major series. Pfizer's second booster is identical to Pfizer's first booster, which was identical to Pfizer's first two doses of Covid-19. Moderna's second booster is the same dose as its first, which was half the dose (50 micrograms) of the Moderna Covid-19 vaccines from the primary two-dose series.

However, since the weather is getting hotter and humid and activities are gradually moving outside, experts hope it may help slow viral spread. Moderna and Pfizer are also working on new Covid-19 vaccinations that will protect against Omicron variants better than the original mRNA vaccines. A pre-print uploaded to Research Square on April 15 described Moderna's testing of a bivalent vaccine. That new vaccine includes mRNA coding for spike proteins found on the original severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which caused the global pandemic, as well as mRNA coding for spike proteins studding the Beta variant of SARS-CoV-2. Bivalent means the vaccine has two components for your immune system to respond to. It indicates that this new bivalent combination generates more antibodies against the Omicron variety than the present Moderna Covid-19. While it is not yet available to the general public, it may be later this year before the fall.

So what is the final answer? Follow the CDC's recommendation, per its press release: “This is especially important for those 65 and older and those 50 and older with underlying medical conditions that increase their risk for severe disease from Covid-19 as they are the most likely to benefit from receiving an additional booster dose at this time.”

Otherwise, if you're between the ages of 50 and 64, without any underlying medical concerns or regular exposure to potentially infected people, you might want to hold on a second. Then you can check if new Omicron-specific immunizations come out later in the summer. In the meantime, keep up other Covid-19 precautions like social distance and wearing face masks in public.