#New findings about covid vaccine series#

The primary series also offered good protection against infections in the short term (over 80 percent within the first 42 days), but that protection fell to around 60 percent after four months, and 50 percent after nine months. This protection waned over time, going below the WHO recommendation, but stayed relatively high, at around 80 percent against hospitalizations at eight months post-vaccination, and around 85 percent against deaths at six months post-vaccination.

We found that the primary series offered excellent protection against hospitalizations and deaths in the short term, showing over 90 percent protection against both outcomes within 42 days after vaccination. Specifically, vaccines should show at least 70 percent protection against infections and 90 percent protection against hospitalizations and deaths. The WHO has set standards to define whether a vaccine offers adequate protection. The results were published in Lancet Respiratory Medicine. We then combined all the data to better understand how the vaccines' protection changes over time. In total, we identified 68 studies that met these criteria, representing 23 countries. Looked at who got infected, was hospitalized or died due to COVID-19.

Compared people who were vaccinated (either with the primary series or a booster) to people who were unvaccinated įollowed people for at least 112 days after a primary series, or 84 days after a booster dose, and.To answer these questions we sought to identify all studies that: First, how well does the primary series of COVID-19 vaccines protect people (against infections, hospitalizations and deaths) four months or more after completing vaccination? Second, how well does the first booster dose protect people three months or more after receiving it?Īnswering these questions will provide invaluable information for policymakers to make evidence-based decisions, such as the timing of administering COVID-19 vaccine booster doses. With this in mind, we sought to answer two questions. A total of 5.09 billion people have completed a primary COVID-19 vaccination series (i.e., two doses of a two-dose vaccine or one dose of a one-dose vaccine).Īt the end of 2021, several countries began offering booster doses in response to research indicating that the effectiveness of the vaccines may diminish over time, especially against the Omicron variant, which emerged in late 2021, and has become the dominant circulating variant. Today, more than 5.5 billion people (72.3 percent of the world's population) have received at least one dose of a COVID-19 vaccine. Understanding the effectiveness of vaccines remains crucial. The WHO has lifted the Public Health Emergency of International Concern, but ending the ongoing threat of COVID-19 still depends on vaccination and other protective behaviors. COVID-19 vaccination was deemed crucial to prevent the continued spread of the disease, protect those infected from experiencing severe effects, counter the rise of new variants, and ultimately end the pandemic.

New findings about covid vaccine