What have we learned about air pollution and COVID-19? Learn about six air pollutants that are harming your health. Dr Maria Neira explains findings from WHO's new air quality guidelines in Science in 5.

What steps should a school take to keep students and staff safe from COVID-19? What about vaccination? How can families and communities keep themselves safe as schools reopen? Dr Maria Van Kerkhove explains in Science in 5 this week.

Many countries are using the approach of mixing vaccine doses from different manufacturers. What do we know about the safety and efficacy of this approach? What does the evidence tell us about using a fraction of the vaccine dose ? Dr Katherine O'Brien explains in Science in 5 this week.

What does evidence say so far about safety and effectiveness of booster shots? Are their groups who may need them? Should the world be considering booster shots at this stage of the pandemic? Dr Katherine O'Brian explains in Science in 5 this week.

Are you planning to quit tobacco during the pandemic? What risk does COVID-19 pose to a tobacco user? Learn how the tobacco industry lured people to consume tobacco during the pandemic. Dr Hebe Gouda explains the health benefits of quitting tobacco in Science in 5.

If you have COVID-19, is it safe to breastfeed your baby? Is it safe to get vaccinated against COVID-19 if you are breastfeeding? How can you keep your baby safe while breastfeeding if you have COVID-19? Dr Laurence Grummer- Strawn explains in Science in 5.

If you had COVID -19 do you still need the vaccine? How long should you wait after recovery to get vaccinated? What do we know about natural immunity vs vaccine induced immunity? WHO's Chief Scientist Dr Soumya Swaminathan explains in Science in 5 this week.

If you are fully vaccinated can you still get COVID-19? How frequent are breakthrough infections and what does COVID-19 look like if you are fully vaccinated. WHO's Dr Kate O'Brien explains in Science in 5.

If you are living with HIV, what are your risks? Should you be prioritized for vaccination? Are vaccines safe for you? WHO's Dr Meg Doherty explains in Science in 5.

If you have recovered from COVID-19 but are still experiencing certain symptoms you could have post COVID-19 condition or "long COVID". What are these symptoms? How long do they last and are there any treatment options? Dr Janet Diaz explains in Science in 5.