What We Know About BA.5 & COVID Vaccines

Summer is here and so is travel, crowds and large gatherings.  And in the last 6 months we have seen an unprecedented number of SARS-CoV-2 (COVID) variants arise, with a new variant almost each month.  This virus has had many opportunities to mutate and evolve with removal and reduction in layers of protective measures throughout the world and now we are now seeing a rapid increase in global cases, of over 30% in the past 2 weeks, primarily due to a new variant. 


What is the BA.5 variant?

  • BA.5 is an Omicron SARS-CoV-2 sub-variant (we’ve had Alpha, Beta, Gamma, Delta, etc, and this one of the many versions of the Omicron lineage, but still very different from original Omicron, BA.1.1529).  It is currently the dominant variant causing infections in the U.S. and many other countries.  
  • Omicron BA.5 is now the most contagious version of SARS-CoV-2. It is highly transmissible which means that it is spread from one person to others very easily and quickly.  As SARS-CoV-2 evolves, it becomes increasingly more transmissible due to new ability to evade our immunity and/or being able to transmit faster or more effectively. It is airborne, meaning it is easily transmitted in the air, like smoke, even with brief, passing interactions with others, whether outdoors or masked.  In comparison, colds are not airborne, are transmitted in large droplets, and require a lot more contact for a person to become infected.  This means we need to adapt our methods of preventing infection and it is time to level up your masks.  Though last summer being outdoors provided us with a lot more protection against infection, that’s not the same this year. For best protection use an N95 with a tight seal around the nose and mouth and behind the head straps when outside of your home indoors. When outdoors with others outside of your own home, for best protection, use an N95, KN95 or KF94 mask if you cannot stay well distanced (over 6 ft in complete open air conditions). 
  • It is better able to evade our immunity.  What does this mean?  It means it is less likely to matter if you have been previously infected and vaccinated in regards to becoming infected.  The vaccines are still very effective in preventing severe disease and death, but up to date boosters are necessary to keep up those levels of protection against the most severe COVID outcomes. BA.5 being better to evade our immunity also means even if you had COVID with a previous variant, you can become reinfected again now.    
  • Symptoms continue to be similar to previous variants, ranging from no symptoms at all to cold symptoms, gastrointestinal symptoms or more severe COVID pneumonia.  But unlike the original Omicron, loss of sense of smell and taste are being reported more commonly again, as well as symptoms of higher fevers, headaches and neck stiffness.  


Why is it still important to get boosted? 

  • Additional vaccine doses (boosters) are necessary for two reasons: 
    1. to counter waning immunity (a natural reduction in the amount of antibodies made by our bodies in response to the types of vaccines available)
    2. Since this is a virus that is constantly changing, there is no single vaccine or infection that can provide lifelong immunity. 
  • Though vaccines will vary in how much protection they can provide against infection and mild-to-moderate symptomatic illness, they are still providing high levels of protection against severe illness and death.  
  • Long COVID and damage to multiple organ systems is a concern with any COVID infection and can affect anyone. Additional vaccine doses can help reduce the risk of developing long-COVID. 
  • 2/3 of Americans ages 18-49 have yet to receive their first booster dose.  Less than 20% of Americans 50-64 eligible for a second booster dose have received one. If you are 50 years or older or at higher risk for complications from COVID, then you are eligible for a second booster dose. 


I already had COVID, isn’t that the same as a booster? 

  • How beneficial protection is from an infection with a previous variant is entirely dependent on the next circulating variant.  As this virus continues to rapidly evolve, newer versions can be similar to previous ones and be easily recognized by our antibodies, or have many mutations that make it easy to escape our immune response.  BA.5 is the latter, and previous infection will not provide complete protection against an infection with BA.5. (Coronaviruses in general are famous for this!) 


Why is it still important to take precautions? 

  • With every infection you are taking a gamble with how much damage COVID can cause to your immune system and body.  Some of this damage can be permanent and/or result in impairment. We know that there is an increased risk of developing diabetes, strokes, heart attacks and death even after a mild-COVID infection in healthy, young people.  The risk of Long-COVID and damage to multiple organ systems- kidneys, liver, lungs, gut and neurological systems is also there. Whether repeat COVID infections increase the risk of Long-COVID is also being investigated. 
  • By curbing infections is how we start to work our way out of this pandemic.  Each individual that takes measures to not become infected is one less opportunity for this virus not to continue to evolve to escape our treatments and vaccines. 


Will getting a booster now prevent me from getting the updated omicron vaccine in the fall? 

  • No. If you are due for a second dose booster do not wait for the new omicron vaccine as the risk for infection is now.  BA.5 and other new variants are currently circulating widely, significantly increasing the risk you will become infected now or in the next several weeks.  You will still be able to receive the new vaccine once it is available or shortly after, and there is no guarantee that BA.5, or even omicron, will be the version of the virus spreading at that time. 


We will continue to have to respond to new versions of this virus as it continues to evolve.  Like most viruses we have developed vaccines for, it continues to cause a broad range of infection from asymptomatic to dangerous and lethal infections.  Polio and measles are good examples of viruses that cause mild or no symptoms in the majority of people, but severe disease and death in the most vulnerable, and in healthy individuals can have lifelong consequences by causing disability or immune impairment.  Worldwide vaccination and eradication campaigns are the reasons why most of us are unfamiliar with the risk those viruses pose.  


Sometimes we will be lucky with a version of the virus that results in less severe infections due to where our immunity is as a population, and which mutations the virus has, like the original Omicron variant. But viruses have many evolutionary advantages over us, including no incentive to become milder or weaker.  We protect ourselves with sensible layers of protection. With Hepatitis A, which is transmitted via contact with contaminated stool through water or ingestion of contaminated food, we use a (very effective) vaccine to reduce the risk of infection, and have food handling, water source treatment and screening, and hand washing practices in place to prevent infections.  SARS-CoV-2 is airborne, meaning it is able to be transmitted by inhaling the same air as an infected individual. So indoor air quality measures such as air purification and filtration policies and practices, mask use indoors and in crowded areas, and improvement of airflow, are all simple measures to reduce risk of infection significantly. 


Our current vaccines provide crucial protection against severe disease and death, and reduce the risk of development of long term complications. A promising step is inhaled intranasal vaccines (similar to the flu shot option for children), that will reduce the risk of infection and help further curb the cycle of reinfections that keep this virus circulating.  With these layers of protection in place, it is possible to get this virus to manageable levels without frequent boosting and ongoing widespread impairment of millions worldwide.  


  1. Weekly epidemiological update on COVID-19—6 July 2022. (n.d.). Retrieved July 12, 2022, from
  2. Implications of the emergence and spread of the SARS-CoV-2 variants of concern BA.4 and BA.5 for the EU/EEA. (2022, June 13). European Centre for Disease Prevention and Control.
  3. CDC. (2020, March 28). COVID Data Tracker. Centers for Disease Control and Prevention.
  4. Azzolini, E., Levi, R., Sarti, R., Pozzi, C., Mollura, M., Mantovani, A., & Rescigno, M. (2022). Association Between BNT162b2 Vaccination and Long COVID After Infections Not Requiring Hospitalization in Health Care Workers. JAMA.

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