“Climate change puts more pollen in the air”

14 June 2022

Christer Janson

"Since 1990, the number of pollen allergy sufferers has increased by around 20-25 percent", says Christer Janson, who is a Professor at the Department of Medical Sciences.

Hello to Christer Janson, Professor of Respiratory, Allergy and Sleep Research. What percentage of the population suffers from pollen allergy?

“We usually say that 25 per cent of adults suffer from it. This makes it one of the most common complaints. Some people have occasional problems and can take antihistamine tablets to help, while others find their medication doesn’t work all that well and they have problems all season.”

Has this figure increased, and if so why?
“It has, yes. We’ve been monitoring the situation since 1990, and we’ve seen maybe a 20, 25 per cent increase. It’s also clear that over the same period, the number of people with allergic reactions – which isn’t quite the same as being allergic to pollen, when you have antibodies to it – has also increased. This is linked to the fact we’re seeing warmer weather now on account of climate change, which puts more pollen into the air.”

How has research helped to counter the problems faced by the people who suffer most?
“It’s improved matters. There are other treatments, specifically allergen immunotherapy (AIT). We often refer to that as an allergy vaccine. It can be administered as tablets now – it was only available as injections previously – and that’s made it more accessible. But far too few people are given this. We’re a long way behind Norway and Denmark.”

Is there any phase in life where pollen allergy is more likely to start?
“Pollen allergy most commonly begins during adolescence and up to the age of 30 or so, but things are different now to how they used to be and we’re seeing more and more older people starting to suffer from this allergy. We used to think that allergies got better with age, but we no longer believe that.”

What’s happening in research in this field?
“We have a number of projects in progress at Uppsala University. One such project involves people who we know are allergic to pollen – we want to see how they react during and after the pollen season. We’re particularly interested in something called mast cells, which are key to allergic reactions. We want to see whether the mast cells change from their initial stage when they migrate from the bone marrow, where they’re formed, and out to the tissues, where they mature and become mast cells. The initial stage of mast cells is hard to find, but we’ve managed to describe it. We want to see what happens in them before and after an allergy develops. We also want to see what happens in the body during AIT treatment, and why it works.”

As a researcher, what would you like to understand more when it comes to allergies?
“We want to understand even more accurately the mechanisms that activate mast cells so that we can use this to develop new therapies. So we have two strategies. Describing how common allergies are, and continuing experiments to find out how things happen and what happens in the body and the mast cells so that more people get the right treatment for their allergies.”

Last modified: 2021-02-14