Now that people who are over 50 or those who are immunocompromised are eligible for a second COVID booster, you may be wondering whether you should switch up the type of vaccine you get for your fourth dose.

Evidence suggests that doing so for the third dose produces a stronger, more robust immune response, likely because the vaccines stimulate our immune system in different ways. Although there isnt much data on the fourth dose, infectious disease experts suspect that mixing up your second booster will be similarly beneficial.

While there may be a slight edge to mixing vaccines, youll still be well protected against severe outcomes if you decide to stick with the same type of shot for your second booster, according to infectious diseases experts.

The one caveat is that anyone who initially got the Johnson & Johnson vaccine will want to follow up with one of the messenger RNA (mRNA) vaccines like Pfizer or Moderna as evidence consistently shows they provide stronger protection. But the mRNAs boost each other well and can be safely interchanged.

When it comes to the numbers that matter the most, which is preventing hospitalization, severe disease and death, there is literally no difference, Onyema Ogbuagu , a Yale Medicine infectious diseases specialist, told HuffPost.

What To Know About Mixing And Matching Booster Shots

The data is limited on how mixing vaccines for your fourth dose specifically impacts protection, but prior research shows that the mix-and-match strategy with the first three doses provided a broader immune response.

A study from the National Institutes of Health found that boosting with a different type of shot than what was previously administered was associated with higher antibody levels than people who boosted with the same type of shot.

If you switched, you actually had more of an immunologic response than if you just continued with the same vaccine, said Robert Murphy , a Northwestern Medicine infectious diseases doctor.

This is likely because the body responds to the vaccines differently, which ultimately helps produce a broader immune response.

I think that there is evidence that mixing and matching between the mRNA vaccines may have some benefit because they slightly stimulate the immune system in different ways, said Amesh Adalja , an infectious diseases expert and senior scholar at the Johns Hopkins University Center for Health Security. Adalja believes this same biological principle would apply to the fourth dose, too.