"I don't want any mother to have to think, 'What if my kid has polio?' " the actress tells PEOPLE
Kristen Bell polio vaccination

Jon Kopaloff/Filmmagic

When Kristen Bell found out that polio is still an issue for young children around the world, she knew she had to get involved.

“It’s a viral disease and it mostly attacks children under the age of 5 — it robs them of their mobility,” the actress, 35, tells PEOPLE. “I have two children under the age of 5, and I can tell you, their mobility is currently their most prized possession.”

“Their ability to scoot around, run around, jump off of things — I couldn’t imagine if they didn’t have the ability to do that,” she continues. “Thinking about what my kids would be like if they had polio, it’s unacceptable. I don’t want any mother to have to think, ‘What if my kid has polio?’ ”

Bell has joined Rotary’s This Close campaign to educate people and raise funds for the eradication of the disease.

“I think it’s so great that the campaign’s message is optimism,” she says. “In 2015, there were less than 50 cases reported. This is such an accomplishable goal. I’m raising awareness, and being optimistic about polio’s end is my way to stand by the campaign.”

Bell — who is also a spokesperson for This Bar Saves Lives, which donates a packet of food to a child in need for every snack bar sold — hopes her commitment to giving back is something she can instill in her daughters, Lincoln, 2, and Delta, 9 months.

“I always want to expose them to other lifestyles, other demographics, other income levels,” she explains. “I think it’s wildly important for someone’s sense of character to have seen things outside their bubble. I want my girls to know that we are extraordinarily lucky, and we have an obligation and responsibility to help everyone else.”

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For more on Bell’s mission to end polio, pick up the latest issue of PEOPLE, on newsstands Friday.

— Gabrielle Olya