Published onParents PACK
It is probably fair to assume that we are ALL tired of COVID-19 — we’re tired of hearing about it, talking about it, testing for it and planning around it. We’ve had it! But SARS-CoV-2, the virus that causes COVID-19, is not done with us. So, as we wait to see what’s in store this fall, we thought it might be helpful to address some of the latest COVID-19-related matters that have been generating questions.
Do I really need a COVID-19 booster? If so, how many and when?
One of the areas of COVID-19 vaccine recommendations that has been difficult to keep up with is booster dosing. Currently, most (but not all) people are recommended to get at least one booster dose. The recommendations are based on:
- Which type and brand of vaccine an individual received
- The person’s age
- The person’s immune system status (immune-competent or immune-compromised)
- The presence of one or more medical conditions that put someone at risk of severe COVID-19
To help navigate the complex recommendations, the Centers for Disease Control and Prevention (CDC) has published an “At-a-glance” COVID-19 vaccination schedule. We also have a summary on our COVIDVaccineAnswers.org page (See “Do I need another dose of the COVID-19 vaccine?”), and your healthcare provider or vaccination clinic staff will be able to help. But knowing the booster dose recommendations does not necessarily answer the questions many people have about the reasoning behind booster doses, so let’s dive a bit deeper.
Protection against mild disease is mediated mostly by the presence of high levels of neutralizing antibodies present at the time of exposure. Because neutralizing antibodies in the bloodstream usually last for only a few months, protection against mild disease is relatively short-lived. Protection against severe disease, on the other hand, is mediated by memory cells, which are relatively long-lived. Therefore, protection against severe disease is typically longer-lived. For the most part, booster dosing should be reserved for those in high-risk groups who cannot handle even a mild infection due to underlying health conditions or an immune system that functions less efficiently as a result of taking immune-suppressive drugs or being advanced in age. As of now, there is no clear evidence that healthy young people require booster dosing.
What can you tell me about these mixed variant vaccines?
The current (i.e., original) COVID-19 vaccines used the spike protein from the strain of SARS-CoV-2 isolated in Wuhan, China. However, by the time these vaccines were produced, tested and approved, the virus had mutated, and a version known as Omicron was the predominant cause of infections. Luckily, the vaccines remained effective in protecting against severe disease caused by the early Omicron strain and the Omicron subvariants. Currently (in the summer of 2022), the dominant strains of SARS-CoV-2 are Omicron subvariants BA.4 and BA.5.
As a result of the changing virus, both Pfizer and Moderna started working to create updated mRNA vaccines. Early efforts were directed toward the original Omicron variant, called BA.1. Initial studies of versions with BA.1 showed that antibody responses improved when tested against the BA.1 virus. However, since the virus has changed further, the FDA has now directed vaccine manufacturers to create a bivalent vaccine, meaning one that protects against both the original virus spike protein and the one found in BA.4 and BA.5. Although BA.4 and BA.5 are distinct subvariants, the part of the virus that would be used for the vaccine is similar, such that manufacturers can use either and do not need to include both.
While the government has committed to purchasing these new vaccines, it will be imperative that data are generated to understand how the immune system responds to these newer versions in various situations, so that vaccine recommendations can be tailored to the different sub-populations throughout the U.S. (e.g., unvaccinated, primary vaccinated, vaccinated and boosted, immune competent, immune compromised).
Did I hear there is a new type of COVID-19 vaccine?
Yes! Recently, a protein-based COVID-19 vaccine, Novavax, was approved for use in U.S. adults 18 years of age and older. This vaccine is given as two doses separated by three to eight weeks. Rather than having our cells produce the spike protein, like is done with the mRNA and viral-vector vaccines, this vaccine delivers the spike protein directly. It also contains an adjuvant that elicits a better immune response than if the protein is given alone. The adjuvant used in the Novavax vaccine is called Matrix-M™, which is also used in the shingles vaccine (Shingrix®).
Why do the COVID-19 vaccine recommendations keep changing?
Most vaccines are preventing diseases that have been around for decades or centuries. This is relevant for two reasons. First, it means we know a lot about the disease and the pathogen that causes it. Second, it means that the vaccine, too, has often been around for decades. As such, the vaccine and recommendations for its use change rarely and minimally compared to what we have experienced with COVID-19.
The ride with COVID-19 has been so “topsy-turvy” because scientists were trying to learn about the virus and the disease while simultaneously working to develop treatments and vaccines. Indeed, it was about two years ago in the July 2020 Parents PACK newsletter that we discussed the “front-row seat to science” caused by COVID-19. Check it out again for a reminder of where we were and how far we have come.
If you have other questions, please check our dedicated page, COVIDVaccineAnswers.org, which has answers to dozens of questions, and if you don’t see your question, email us using the form on the page.
Materials in this section are updated as new information and vaccines become available. The Vaccine Education Center staff regularly reviews materials for accuracy.
You should not consider the information in this site to be specific, professional medical advice for your personal health or for your family's personal health. You should not use it to replace any relationship with a physician or other qualified healthcare professional. For medical concerns, including decisions about vaccinations, medications and other treatments, you should always consult your physician or, in serious cases, seek immediate assistance from emergency personnel.