How do You Know The Effectiveness of COVID-19 Vaccine

Vaccine effectiveness refers to work the corona-virus shot in people.

In this week, Moderna said its vaccine appear nearly 95% effective. Pfizer announcement is also appeared with same effectiveness shot.

Those number raised the hope around the world that it could help and put the end to the pandemic.

Effectiveness numbers may get changed as the vaccine studies had been based on less than 100 cases in each study. But early study provides strong signal that vaccine could prevent majority of disease.

US Officials said they would consider it to use if it get at least 50% effectiveness. There was concern that the corona-virus vaccine might be as effective as flu vaccines ranging between 20% to 60% in recent years.

Early effectiveness does not tell whole story. Scientists need to understand that how the vaccine will work on different aged groups and demographic categories.

For both vaccines, the interim results were based on people who had COVID-19 symptoms and prompted to vaccinate. That means we don't know whether someone who is vaccinated might still get infected even if they don't have symptoms and spread virus.

Also unknown whether the shot will give the lasting protection or whether the booster will be required.