The 2016 holiday shopping season started with a dramatic spike in malware infections, and that spike has not let up.

Enigma Software Group reports that as of December 19th, malware infections on its customers’ computers are 99.23% higher than the average number of infections in the month prior to the holiday shopping season starting on Black Friday.

The infection rate is tracking much higher than the infection rate in 2015, which saw an 84% spike. In 2014 the spike was 42%.

“We believe the continued spike in malware is due in large part to increased online activity by holiday shoppers, and increased efforts on the part of malware makers to take advantage of those shoppers,” said ESG spokesperson Ryan Gerding.

The busiest day so far for malware infections was not on Cyber Monday. Instead, it was Wednesday, Dec. 14. That day saw infections 120.06% higher than normal. Cyber Monday’s spike was 118.34%.

“We know that one of the most common ways to trick people into installing malware is by sending them fake emails that look like they are coming from legitimate online retailers,” Gerding said. “We think the reason there’s an even bigger spike a couple of weeks after Black Friday is because that’s the time when online shoppers are in the heart of their buying and package tracking. Cybercrooks know this and will send fake emails saying there’s a problem with an order or promising tracking information. In reality, it’s just a link to malware. But they know the days leading up to Christmas are when people are much more likely to be expecting those kinds of emails from legitimate retailers.”

This link (http://tinyurl.com/jjt9kdq) provides tips to help protect computers against malware during the holiday season and beyond.