Do <span> tags hurt in regards to SEO?

For example would the following code penalize you in regards to SEO?

<h2>Singles events across the UK! <span>Including Bristol, Manchester, London, Birmingham &amp; Newcastle.开发者_JS百科</span></h2>

Would the content inside the <span> tags be regarded as less important?

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The tag on its own shouldn't, but be wary if you're setting the span to display: none in a deliberate attempt to hack SEO, you may get penalised.

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You can never be sure about SEO but the answer is no, it doesn't hurt the search engine rankings.

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Span is not required in the header tag, unless for a purpose (when an author wishes to assign style information to a set of elements). The documents are being read by a machine which are fed specific instructions and structure to process the meaning of that content. It depends.