Of those 12'400 people who were infected after getting the vaccine, 12'331 had only received the first shot. Pfizer themselves have said both shots (spaced apart) are required to achieve the proper immunity.
69 people got both shots and still got infected, but there's no data yet to say whether they'd caught it before they got the second shot, or in the period between getting it and building up immunity, or afterwards and contracted it anyway.
Pretty sure the UK have also been leaning towards only letting their population get the first shot so as more people can get a lesser-effective result rather than fewer people getting a more effective one, despite some medical experts warning against doing it that way. Hopefully the news from Israel shows why it's better to follow pfizer's protocol and let people have the two jabs.
https://www.globaltimes.cn/page/202101/1213566.shtml