根据给定的关键字，生成一组相关的新闻标题。

提供关键字 "COVID-19"。
1. COVID-19 cases surge across the world.
2. Researchers make progress in developing COVID-19 vaccine.
3. Schools and businesses adapt to new COVID-19 guidelines.
4. Governments implement lockdowns to contain the spread of COVID-19.
5. COVID-19 causes economic downturns and job losses globally.