update handlebars template with new data in node+express

I've managed to get my handlebars working in a node+express app and loading in data from tweets based on a hashtag which I'm retrieving no problems and rendering the tweets on the page the first time no problem.

The issue I have now is trying to update the template with new tweets that come in.

I have in my routes the following code:

    new twitter.TwitterStream().getHashTagStream(tweetsRetrieved);

    function tweetsRetrieved(tweets) {
        twitterSearchResults = tweets;
    }

    module.exports = function(app) {
        app.get('/', function (req, res){ 
            res.render('index', twitterSearchResults);          
        });
    };

I've tried setIntervals around the rendering and getTweets method and when console logging I do see my response from Twitter with the latest tweets but the template isn't updating.

Any help would be greatly appreciated.

Thanks

Tom