It has been four months since the United States began vaccinating on December 20 last year. How is the epidemic in the United States today? How safe and effective are vaccines in the real world? What are the key contributions of Chinese scientists in the development of vaccines in the United States?

Based on more than 20 years of experience in new drug development and clinical research in the United States, the author will briefly describe them one by one as follows.

1. Current status of vaccine use in the United States

As of today (May 1), the United States has injected 159.8 million doses of Pfizer's vaccine, 130.9 million doses of Moderna's vaccine, and more than 18 million doses of Johnson & Johnson's vaccine. doubled the projected target. [1]

More than 80% of people over 65 have received at least one dose, and nearly 70% have been fully vaccinated.

The 18-29-year-old group has just opened for three weeks of vaccination, and currently 34.2% have received at least one dose, and 18.5% have been fully vaccinated.

A Phase 3 clinical trial of Pfizer's vaccine in adolescents (12-15 years old) had interim results last month and was nearly 100% effective in 2,260 people. The FDA is expected to approve the Pfizer vaccine for use in the adolescent population soon.

Clinical trials in children aged 6 months to 12 years are underway, with results expected by the end of the year.

Proportion of U.S. population by age group who have received at least one dose of vaccine
Proportion of U.S. population by age group who have received at least one dose of vaccine

2. U.S. Vaccine Real World Study Safety and Efficacy Data

(1) Real-world security tracking results:

The U.S. Centers for Disease Control (CDC) released a safety summary report on the first 22 million people in the United States to receive the new crown vaccine on January 27. The safety data after mass injection of the vaccine are consistent with the results obtained during the clinical study. All those who developed allergic reactions were successfully treated with no other serious problems. [2]

(2) Real-world effectiveness data of Pfizer’s vaccine in Israel:

Between December 20, 2020, and February 1, 2021, 596,618 people in Israel received the Pfizer vaccine. The Israeli health department matched the unvaccinated controls in a 1:1 ratio based on the population's area of ​​residence, age, health status, and other characteristics. The results showed that among the nearly 600,000 people who received two doses of the Pfizer vaccine, there was a 94% reduction in symptomatic infections; an 87% reduction in related hospitalizations; a 92% reduction in severe cases; and no deaths from related infections. [3]

The effectiveness of large-scale vaccine injections in the real world in Israel is highly consistent with the results of Phase III clinical trials in the United States, showing surprising effects. The results of this study have strengthened the confidence of countries in the world to promote vaccine injection.

(3) Real-world data of mRNA vaccines in the United States:

On April 2, the CDC released an interim report on a study of the real-world effectiveness of two mRNA vaccines, including protection against asymptomatic infections, in the U.S. on the front lines of the pandemic.

Complete immunity (≥14 days after second dose) against SARS-CoV-2 viral infection (symptomatic + asymptomatic) is 90% effective
Partial immunization (≥14 days after the first dose to before the second dose) is also up to 80% more effective (symptomatic + asymptomatic)
This result demonstrates that mRNA vaccines are effective in preventing real-world SARS-CoV-2 virus infection

On April 28, the CDC reported that after full immunization, hospitalizations for people over 65 were reduced by 94 percent. [4]

(4) Will the infection still occur after complete vaccination?

The infection after vaccination is called the "breakthrough infection" of the new crown vaccine, that is, the virus breaks through the immune protection induced by the vaccine. CDC updates data on "breakthrough infections" in a timely manner. As of April 26, 9,245 "breakthrough infections" had occurred among the more than 95 million vaccinated people in the United States. The incidence is 9,245/95,000,000 = 0.01%.