Combatting Climate Change and Allergies

By Christina Phillis 


If you’ve noticed your allergies lasting longer than normal lately, you can’t place all the blame on your neighbor’s cat. Higher-than-normal temperatures caused by climate change are elongating allergy season and lowering air quality, worsening allergies for about 25 million Americans. According to a 2010 report produced by the Asthma and Allergy Foundation of America (AAFA) and the National Wildlife Federation (NWF), pollen season lasted 11 to 27 days longer between 1995 and 2011 due to warmer temperatures in the U.S.

Also contributing to the severity of allergy season are carbon dioxide levels in the atmosphere, which have increased by about 40 percent since the 1700s. Since carbon dioxide is required for plant survival, the increased levels can cause plants to grow faster and larger. Ragweed, which is the allergen that causes hay fever in 75 percent of sufferers, grows faster, produces more pollen per plant, and exhibits higher allergenic content because of higher carbon dioxide levels. When researchers in one study increased carbon dioxide levels from current levels, production of Amb a 1, the allergenic protein in ragweed, increased by 70 percent. Larger ragweed plants that produce more pollen later into the fall also add to the longevity of allergy season. If fossil fuel emissions continue at their current level, pollen production is expected to increase by 60 to 100% by around 2085.

Where and when plants can grow is also in flux as the growing season gets longer. Spring arrives an average of 10 to 14 days earlier than it did 20 years ago, and many plants, unable to tolerate the hotter conditions, are spreading north to higher elevations. The habitat for oaks and hickories, two highly allergenic tree species, could significantly expand under these conditions. 

Reducing Allergy Risks

The report from the AAFA and the NWF makes recommendations on what can be done to reduce allergy risks caused by climate change. Relying more on solar energy as opposed to burning fossil fuels has the dual effect of reducing global warming and improving air quality. 

Placing restrictions on the planting of pollen-producing species of trees is another option, but any effects may be significantly delayed due to the long life spans of trees. The report also points out that this option would have to be weighed against the value of the plants for wildlife, among other natural benefits.

Urban design that incorporates more parks and trees, reflective coatings on structures, and “green” roofs on buildings would decrease the amount of heat generated in cities, thereby decelerating the production of pollen

The Toll of Allergies

According to the American College of Allergy, Asthma, and Immunology, allergies affect 50 million people in the United States — fully 30 percent of adults and 40 percent of children — and that number is increasing. Allergies are the fifth leading chronic disease in the U.S. in people of all ages and the third most common chronic disease in children under 18 years old. According to a brief produced by the National Center for Health Statistics, 11.1 million people were diagnosed with allergic rhinitis in 2012. Americans with nasal swelling spent roughly $17.5 billion on health care costs and lost more than 6 million work and school days in 2010, according to the Academy of Allergy and Asthma in Primary Care.

Finding Allergy Relief

While allergy sufferers patiently wait for improvements in air quality and climate, there is a fairly new treatment available — and it doesn’t require getting shots once a week. In 2014 the FDA approved Ragwitek, an immunotherapy developed by Merck, as the first allergen extract to be administered sublingually, or under the tongue, to treat short ragweed pollen-induced allergic rhinitis, more commonly known as hay fever.

“The approval of Ragwitek offers millions of adults living with ragweed pollen allergies in the United States an alternative to allergy shots to help manage their disease,”

said Karen Midthun, MD, director of the FDA’s Center for Biologics Evaluation and Research.

Ragweed pollen season in the United States can start as early as August and last until November. Those suffering from allergies brought on by ragweed pollen display the following symptoms: sneezing, runny or itchy nose, stuffy or congested nose, or itchy and watery eyes.

“During the season, many patients with moderate to severe allergic rhinitis experience nasal and ocular allergy symptoms at their worst while taking symptom-relieving medication. These patients often have multiple sensitivities,” said David Skoner, MD, director, Division of Allergy and Immunology, Allegheny Health Network, and a clinical investigator in Merck’s sublingual allergen immunotherapy tablet program.

Clinical Study of Ragwitek

Five clinical studies were conducted to assess the safety and efficacy of Ragwitek in 1,700 adults. After the studies were concluded, Merck submitted a biologics license application to the Allergenic Products Advisory Committee to gain FDA approval.

To establish efficacy in these studies, rhinoconjunctivitis daily symptom scores (DSS) and daily medication scores (DMS) were self-reported and the sum of both scores was combined into the total combined score (TCS).

The FDA considers an allergen immunotherapy effective if the TCS has an average difference relative to placebo of less than or equal to -15 percent and if the upper bound of the 95 percent confidence interval is less than or equal to -10 percent.

The first study comparing Ragwitek to placebo was conducted with patients from 18 to 50 years of age. About 22 percent of the subjects had mild asthma and some were using a low daily dose of inhaled corticosteroid. In addition to short ragweed allergies, 85 percent of the group were also sensitized to other allergens. After taking Ragwitek, subjects reported significant reductions in nasal and ocular symptoms and decreased use of other allergy medications. The difference in TCS between the Ragwitek and the placebo was -26 percent and the 95 percent confidence interval was between -38.7 percent and -14.6 percent, indicating an effective treatment.

Patients can start taking Ragwitek as early as 12 weeks before the onset of allergy season and throughout to combat its effects. The first dose is administered under the supervision of a physician who monitors the patient for signs or symptoms of a severe systemic or severe local allergic reaction. If the first dose is administered without any issues, the patient can start taking Ragwitek at home.

Although more research is needed to directly combat allergy symptoms and stave off the escalating risks related to climate change, help is on the way.

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