A recent study showed some promising results that azelastine nasal spray may prevent COVID-19 infection. More research is needed to know if this is true.
❓ What is azelastine?
Azelastine (Ah-zeah-las-teen) is an allergy medication that works by blocking histamine, the substance your body releases when you have an allergic reaction. Histamine causes allergic symptoms like a runny nose and sneezing, itchy and watery eyes, itching hives, swelling and congestion. So azelastine is part of a group called anti-histamines, because it blocks the release of histamine.
It is usually available as a nasal spray or eye drops.
❓ Does it have any side effects?
Yes, like most drugs, it can produce some side effects that are typical for an allergy nasal spray and include the risk of nosebleeds, drowsiness, dizziness, and a bitter taste in the mouth.
❓ Why do researchers think azelastine nasal spray might prevent COVID-19 infection?
The recent buzz in the press is because of a new phase 2 clinical trial where the researchers tested the drug’s ability to prevent COVID-19 infection in humans. Previous studies of azelastine have also shown that it may show antiviral activity against RSV, influenza, and COVID.
One study found that it showed antiviral activity in the lab using a process called computational drug repurposing.
Researchers believe that there are essentially three ways how it might work against COVID-19 infection:
1️⃣ It keeps the virus from entering your cells by attaching to the door the virus normally uses to get in, called the ACE2 receptor.
2️⃣ It lowers a protein called ICAM-1 that helps some viruses infect and is involved in inflammation
3️⃣ It stops the virus from making copies of itself by blocking Mpro protease.
Tell me more about this recent study –
❓ What were the results?
In a nutshell, folks who took the azelastine nasal spray ended up having fewer COVID-19 infections compared to those who only used the placebo (or “mock” spray).
❓ Are there any weaknesses or limitations?
No study is ever perfect, even gold standard clinical trials. There are several limitations to this recent azelastine clinical trial. This was a single-center study, which means that only one clinic was responsible for enrolling all participants. Generally, multi-center studies are considered stronger because it is less likely that the study was biased by the geographic location of the center. More than 90% of study participants in this study were white, while less than 1% were noted to have African ancestry. And although the study was open to members of the public, the way folks were recruited meant that those taking part did not necessarily represent the general population. Invitations were sent to hospital workers and medical students, and posters were displayed in and around local pharmacies, the university campus and on some social media.This could have led to younger, healthier and more educated people taking part in the study. This could have skewed the results and is a type of selection bias.
The study sample is also relatively small – only 450 people. This is a normal size for a phase 2 clinical trial, and may seem like a lot, but it is not enough to know if the results will apply in the general population. Plus, the study was also short— the researchers only followed the treatment and placebo groups for 56 days, and there were very few infections in both groups.
A great strength of the study is that it was a double-blind randomized placebo-controlled trial. This means both the people taking part AND the researchers didn’t know who was getting which spray and folks were selected into either group at random. And finally, the azelastine spray was compared to a “mock” spray that looked and tasted the same, but didn’t contain the key ingredient that was being studied. These types of study are considered the gold standard as they “control” for many factors that might otherwise skew the results (some of those factors are called confounders – here is a great post to explain more).
❓ So what’s the takeaway – should I use the spray to prevent COVID-19 or not?
More research is needed to work out if azelastine is actually protecting folks from COVID-19 or if other factors play a role.
Also, azelastine is not yet approved by any regulatory agency for the prevention of COVID-19, and experts warn against using it as a replacement for other proven ways of preventing infection, such as getting vaccinated and wearing a mask. However, if you suffer from seasonal allergies, and are not already using azelastine spray, it is not recommended that you switch. The evidence is not strong enough yet. Dr. Peter Chin-Hong, professor in the UCSF Health Division of Infectious Diseases, told MSN that azelastine could find a niche as an additional Covid-blocking tool for people who already use the spray for seasonal allergies, but felt that there is insufficient evidence to endorse it more widely.
As with any medication, if you are thinking of starting this for your seasonal allergies, or have any questions, make sure you speak to your trusted clinician or pharmacist to make sure this is the right medication for you.
And as for reducing your risk of getting COVID-19: masking, hand-washing, good ventilation, getting vaccinated and staying home when sick, are great tools in your toolbox!
Stay well, stay curious,
Love,
Those Nerdy Girls
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