Tip/Thought of the Day

What to Know About the Latest Covid-19 Variants

Over the last two years, Covid-19 has adapted and developed new variants, maintaining a hold on the world and making it clear the pandemic is not yet over. The two newest variants of Omicron are the latest to spread across the world, causing a fresh wave of infections.

First spotted by scientists in South Africa in April and linked to a subsequent rise in cases there, BA4 and BA5 are the newest coronavirus subvariants. They have been detected in dozens of countries worldwide, including in the United States, where over 95% of COVID-19 cases are attributed to the new variants.

Omicron BA4 and BA5 have been found to be more infectious than previous variants, with some researchers saying it could be the most infectious viruses known to man. Adrian Esterman, a professor at the University of South Australia, wrote in the journal The Conversation that the latest subvariants have an R0 (R-naught value, meaning how many people could be infected from one other individual, on average) around 18.6, which is at least as transmissible as measles, previously the world’s most infectious virus. To give some perspective, here are some commonly known viruses and their R0 values:

VirusR0 value
Common Cold<0
“Original” Wuhan Covid-19 strain3.3
Covid-19 Delta strain5.1
Covid-19 Omicron BA1 strain9.5
Covid-19 Omicron BA4 and BA5 strains18.6

Not only are the BA4 and BA5 more infectious, but the virus has adapted to better avoid our antibodies and latch onto host cells, making previous infections and even vaccinations less likely to protect from breakthrough infections. But, vaccines and boosters are still the best defense, with studies still supporting that while breakthrough infection may occur more often, the risk of severe illness, hospitalization, and death are much lower if people have been vaccinated and boosted.

“The main reason this variant has become the predominant one that is now circulating is that it is able to evade previous immunity,” said Dean Blumberg, chief of pediatric infectious diseases at UC Davis Children’s Hospital. “Even people who have partial immunity from a previous infection or vaccination can still have a breakthrough infection.”That means even if you were infected in 2020 with Delta or even Omicron BA1 last winter, you can still get BA4 and BA5. Your previous immunity does not protect you from the latest strains.

The good news?

Dr. Blumberg shares that while more virulent, “The good news is that the vast majority of breakthrough infections now are outpatient illnesses. They are not resulting in the kind of severe illness that we saw earlier in the pandemic when no one had immunity, which led to increased hospitalizations and deaths.” This is partially due to the nature of the virus itself not being as virulent as previous strains, but also a testament to the tools we have available to prevent and treat infections.

The CDC shares that while Omicron may cause more mild disease, some people may still have severe disease, need hospitalization, and could die from the infection with this variant. Even if only a small percentage of people with Omicron infection need hospitalization, a large volume of cases in a community could stress and potentially overwhelm a healthcare system which is why it’s important to take steps to protect yourself.

Symptoms and treatment

Symptoms of BA4 and BA5 are reportedly similar to other variants, with the most common being fever, runny nose, sore throat, coughing, fatigue, and muscle pain. Some studies are now finding that some infected with the new variants also experience symptoms like night sweats.

New research finds that with each repeat COVID infection – even asymptomatic infection – your risk for complications increases. This includes an increased risk for:

  • stroke
  • heart attack
  • diabetes
  • digestive and kidney disorders
  • long-term cognitive impairment, including dementia

Each reinfection also carries with it the risk of long COVID or ongoing COVID symptoms that can last for weeks or months after infection.

How to protect yourself


There is abundant evidence that being vaccinated and getting all COVID-19 boosters helps protect you against severe disease. The CDC recently released data that showed the risk of death from COVID was four times higher for those over age 50 who had only the first booster, compared with those who had two boosters. This is particularly important for those age 50+ and immunocompromised. On July 28th, 2022, the Food and Drug Administration recommended including a SARS-CoV-2 omicron component in COVID-19 vaccines that would be used for boosters in the U.S. beginning in fall 2022. This followed an overwhelming vote in support of the adjustment to the booster by the independent Vaccines and Related Biological Products Advisory Committee.


Given how infectious BA.5 is, it’s important for everyone to take all precautions, including getting vaccinated and wearing a well-fitted face mask (N95 or KN95, if possible). We’ve previously shared how masks made of different materials offered varied levels of protection. To recap:

Mask material% particles blocked
fabric mask (multi-layer cotton, jersey, etc)26.5%
surgical mask with ear loops38.1%
surgical mask with ties71.5%
washed two-layer woven nylon mask with filter and metal nose bridge79%
non-woven polypropylene> 95%
N95 (including expired and sterilized)>95%


While infection levels that are published for our communities drastically under represent the reality due to at-home testing that isn’t reported or lack of testing, testing is still an important tool to protect yourself and others. Certain treatments are only available within a short window after symptoms start and a positive test. In order to protect others, if you have had close exposure and/or symptoms, please consider testing to determine whether you should quarantine and reduce the spread of the virus. In the presence of symptoms (or a positive test), follow the quarantine guidance provided by the CDC. You can find up-to-date COVID levels in your county using this tool. As of July 31, 2022, five of the fifteen counties in Arizona have “Medium” transmission levels, and the remaining 10 are categorized as having “High” transmission. You can also read about the different community transmission levels, here.


Scientist are working to determine how well existing antibody treatments fight new variants of COVID-19. Some monoclonal antibody treatments have been found to be less effective against certain the current variants. Other non-monoclonal antibody treatments remain effective against Omicron.

Another option is antiviral pills, such as Paxlovid, which received emergency use authorization in late December 2021. The treatment is available to anyone ages 12 and older who weighs at least 88 pounds, and is at high risk for severe disease. Pfizer recently began Phase 2 and 3 trials in children and teens ages 6 to 17. The at-home oral antiviral pills can reduce the risk of severe illness and death by as much as 89% and can be prescribed by a medical provider. You can read more about Paxlovid and Molnupiravir (which was also provided EUA, but was only shown to reduce the risk of hospitalization and death by roughly 30%), here.

Since the beginning of the pandemic, we’ve amassed a variety of methods to protect against and treat Covid-19. While the pandemic isn’t yet over, these tools have provided us an avenue to more safety continue our lives. But, that protection isn’t without effort- it is our responsibility to ourselves and our communities to stay current on our vaccines and boosters, mask, and test.

-https://www.thedailybeast.com/why-the-new-ba5-covid-variant-is-the-most-dangerous-one-yet repeat infections
















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