Immunotherapy for Allergies: Allergy Shots vs. Sublingual Tablets Explained

What Is Immunotherapy for Allergies?

Immunotherapy isn’t just another allergy pill. It’s the only treatment that actually changes how your immune system reacts to allergens like pollen, dust mites, or bee venom. Instead of masking symptoms with antihistamines, it trains your body to stop overreacting. Think of it like a vaccine-but instead of fighting viruses, it teaches your body to ignore harmless substances that normally trigger sneezing, itchy eyes, or even asthma.

This approach has been around since 1911, when two doctors in London first injected pollen extracts into allergic patients. Today, it’s backed by decades of research and used by millions. The goal? Long-term relief-maybe even permanent. After three to five years of treatment, many people stop needing daily meds altogether.

How Allergy Shots Work

Allergy shots, or subcutaneous immunotherapy (SCIT), involve regular injections of tiny amounts of the allergens you’re sensitive to. You start with very low doses and slowly increase them over time. This gradual exposure helps your immune system build tolerance.

The process has two phases: build-up and maintenance. During build-up, you get shots once or twice a week for several months. Some clinics offer cluster schedules-where you get multiple shots in fewer visits-to speed this up to just 4-9 weeks. Rush immunotherapy, used mostly for severe insect sting allergies, can get you to the maintenance dose in one long day.

Once you reach the maintenance dose, you space out shots to every 2-4 weeks, then eventually monthly. Most people stay on this schedule for 3-5 years. After that, many find their allergies have faded significantly-or disappeared.

What Are Sublingual Tablets?

Sublingual immunotherapy (SLIT) tablets are an alternative to shots. You place a small tablet under your tongue every day. The allergen is absorbed through the mucous membranes, slowly training your immune system the same way shots do-but without needles.

In the U.S., the FDA has approved four tablets: Oralair and Grastek for grass pollen, Ragwitek for ragweed, and Odactra for dust mites. Cat-PAD, approved in April 2024, is the first for cat dander. Each tablet targets one specific allergen. You can’t combine them. If you’re allergic to both grass and dust mites, you’d need two separate tablets.

Dosing varies by product. Oralair is taken daily for four months before and during pollen season. Ragwitek and Odactra are taken year-round. You start the first dose at your allergist’s office because of the small risk of a reaction. After that, you take it at home.

Effectiveness: Shots vs. Tablets

When it comes to results, allergy shots win. Studies show 82% of patients on shots see major symptom improvement, compared to 67% for tablets. Why? Shots can be customized. Your allergist can mix several allergens into one vial-say, grass, tree pollen, and dust mites. That’s important because 78% of allergy sufferers react to more than one trigger.

Tablets, on the other hand, are limited to single allergens. If your symptoms come from multiple sources, tablets won’t cover everything. A Reddit thread with over 1,200 users found that 68% of people who tried both treatments got better results with shots. One user wrote: “After two years of Grastek with only 30% improvement, I switched to shots and got 80% relief.”

Still, tablets work well for single-allergen cases. If you’re only allergic to ragweed and nothing else, Ragwitek can cut your symptoms by half. But for most people with multiple sensitivities, shots are the only option that delivers comprehensive relief.

Convenience and Lifestyle Fit

If you hate needles or have a busy schedule, tablets win hands down. You don’t need to drive to the clinic every week. You don’t have to sit in the office for 30 minutes after each dose. You just pop a tablet under your tongue before breakfast.

A 2022 survey found that 92% of tablet users preferred them for convenience. One respondent, a traveling salesperson, said: “I couldn’t manage weekly shots, but the tablet fits perfectly in my routine.”

But convenience comes with a catch: you have to take it every single day. Miss more than 20% of doses, and effectiveness drops to 45%. Setting phone reminders helps-studies show adherence improves by 37% with reminders.

Shots require more effort. You need to schedule appointments, take time off work, and arrange transportation. About 32% of people quit shots because of scheduling issues. That’s why many clinics now offer cluster schedules: fewer visits, faster results.

Safety and Side Effects

Both treatments are safe when used correctly. But the risks differ.

Allergy shots carry a small risk of systemic reactions-like swelling, trouble breathing, or low blood pressure. Traditional build-up has a 2.1% rate of systemic reactions. Cluster and rush protocols are riskier: rush immunotherapy leads to systemic reactions in 18.2% of cases, with 3.1% needing epinephrine. That’s why rush schedules are only used for life-threatening allergies like bee stings.

Tablets are less likely to cause serious reactions. The most common side effect is mild itching or swelling under the tongue-happens in about 28% of users. Rarely, someone might have anaphylaxis, but it’s far less common than with shots.

One big advantage of shots: you’re supervised. After each injection, you wait 30 minutes in the clinic. If something goes wrong, help is right there. With tablets, you’re on your own. You need to know the signs of a bad reaction and have an epinephrine auto-injector on hand if your doctor recommends it.

Who Should Choose What?

Here’s a simple guide:

• Choose allergy shots if: You’re allergic to three or more allergens, your symptoms are severe, you’ve tried medications without success, or you want the strongest possible long-term results.
• Choose sublingual tablets if: You’re allergic to just one allergen (like grass or dust mites), you can’t commit to weekly visits, you’re needle-averse, or you live far from an allergist.

Experts agree: shots are the gold standard. Dr. David M. Lang from Cleveland Clinic says, “SCIT is the only treatment that modifies the underlying immune response, potentially preventing new allergies and asthma.”

But tablets aren’t a backup-they’re a real option for the right person. Dr. Robert E. Wood from Johns Hopkins notes, “They’re a breakthrough for patients who can’t tolerate injections or don’t have access to allergists.”

Cost, Access, and Future Trends

Insurance usually covers both treatments. Shots might cost more upfront due to office visits, but tablets can be pricier per month. Overall, shots make up 68% of the U.S. immunotherapy market. Tablets are growing fast, especially as new ones like Cat-PAD become available.

There’s a big problem, though: there are only 5,300 board-certified allergists in the U.S. Many rural areas have none. That’s why tablets are gaining ground-they don’t require specialist visits after the first dose.

What’s next? Multi-allergen tablets are in Phase 3 trials and could hit the market by 2026. Researchers are also testing peptide-based therapies that could cut treatment time from 3-5 years to just 1-2. And more clinics are using component-resolved diagnostics to tailor treatments to exactly which proteins you’re allergic to-making therapy even more precise.

Real Talk: What Patients Actually Experience

Google reviews for allergy clinics are full of phrases like “life-changing after two years.” On Reddit, people who switched from tablets to shots say they finally feel normal again-no more constant sneezing, no more eye drops, no more canceling plans because of pollen.

But tablet users aren’t wrong either. They love the freedom. One Amazon reviewer wrote: “I take it while brushing my teeth. No appointments. No needles. I’ve had zero symptoms since year one.”

The truth? Neither option is perfect. Shots require discipline and time. Tablets require daily consistency. But both can change your life-if you pick the one that matches your needs.