Update on AstraZeneca Vaccine

“The AstraZeneca US Phase III trial of AZD1222 demonstrated statistically significant vaccine efficacy of 79% at preventing symptomatic COVID-19 and 100% efficacy at preventing severe disease and hospitalization,” said AstraZeneca in a prepared statement issued on March 22.

 “Vaccine efficacy was consistent across ethnicity and age.  Notably, in participants aged 65 years and over, vaccine efficacy was 80%.”

In addition, the company said, “The vaccine was well tolerated, and the independent data safety monitoring board (DSMB) identified no safety concerns related to the vaccine.”

The company said the interim safety and efficacy analysis was based on 32,449 participants accruing 141 symptomatic cases of COVID-19.

This AstraZeneca-led US Phase III trial included two doses administered at a four-week interval. Previous trials have shown that an extended interval of up to 12 weeks demonstrated greater efficacy, which was also supported by immunogenicity data.

The vaccine can be stored, transported, and handled at normal refrigerated conditions for at least six months.

AstraZeneca is preparing to submit an application for emergency use authorization with the U.S. Food and Drug Administration in the coming weeks. It has been granted a conditional marketing authorization or emergency use in more than 70 countries.  Its emergency use was temporarily suspended in about a dozen countries over concerns about possible rare side effects. The results of its latest trial in the U.S. have helped  European leaders  to buttress people’s confidence in the shot.

It is unclear at this point how much the vaccine will be used in the United States in light of the current roll-out of the Pfizer, Moderna, and Johnson & Johnson vaccines here, but it is expected that AstraZeneca’s vaccine will play an important  role in containing the pandemic on a world-wide basis.

Risk of Community Spread

Two of the charts in the above chart box track: 1) the total number of new COVID-19 cases per 100,000 people in Evanston, Suburban Cook County, Chicago and the State, and 2) the percentage of tests for COVID-19 that were returned positive in the last 7 days.

For total cases in the last 7 days per 100,000 people, IDPH uses a target of 50 cases. CDC says between 10 and 49 cases represents a “moderate” risk of transmission.

For test positivity in the last 7 days, IDPH uses a target of 5%. CDC says between 5% and 7.9% represents a “moderate” risk of transmission. [1, 2 and 3]

Evanston – COVID

The City reported 8 new COVID-19 cases of Evanston residents today, compared to 7 yesterday and 2 on Saturday.    

The average number of new cases per day in the last seven days is 4.7, down from the seven-day average of 7.7 on March 15.

In the last seven days, there was a total of 33 new COVID-19 cases of Evanstonians. The 33 new cases equate to about 45 new cases per 100,000 people in the seven-day period.

The case positivity rate over the last seven days is 0.5%.  

There has been a total of 4,073 COVID-19 cases of Evanston residents during the pandemic, 127 of which are active. 

No Evanstonian died due to COVID-19 in the last 72 hours. The number of deaths due to COVID-19 remains at 114.

Impact of Northwestern University. Northwestern University has posted data on its website reporting that between March 15 and March 21 there were 11 new confirmed COVID-19 cases of NU faculty, students, and staff. The number includes people who live outside of Evanston. The City says it does not know how many of these cases are people who live in Evanston.  [5]

Illinois – COVID

 In the State, there were 1,220 new COVID-19 cases reported today, up from 1,431 yesterday.  

Statewide, the average number of new cases per day in the last seven days is 1,852. The seven-day average one week ago on March 15 was 1,513, so today’s number is up by 22%.

Today’s seven-day average is down from an all-time high of 12,380 on Nov. 17. An accompanying chart shows the trend.

In the seven days ending March 22, the number of new cases per 100,000 people in the State was 102, up from 84 one week ago.

The seven-day case positivity rate for the State today is 2.6% and the test positivity rate is 2.9%.

On a Statewide basis, the number of hospitalizations due to COVID-19 was 1,182 as of midnight on March 18. This is down from an all-time high of 6,171 on Nov. 23.

The number of patients using ICU beds is 233, down from 1,195 on Dec. 1. The number of patients on ventilators is 98, down from 724 on Dec. 1.

On a Statewide basis, there were 22 deaths due to COVID-19 in the last 24 hours, which brings the total to 21,103.

For the last seven days, the numbers of deaths in the State are 19, 17, 34, 12, 25, 22, and 22 today. The seven-day average is 22.

Variants in Illinois

IDPH is reporting a total of 143 confirmed cases of COVID-19 variants in the State: 135 are the variant first discovered in the UK; 3 are the variant discovered in South Africa; and 5 are the variant discovered in Brazil.

Vaccinations in the State

A total of 5,756,795 doses of vaccine have been delivered to providers in Illinois, including Chicago and long-term care facilities. IDPH is currently reporting that a total of 4,747,845 doses of vaccines have been administered.


1/ On Feb. 12, the CDC issued a “K-12 School Operational Strategy.” As part of that strategy, the report says, “CDC recommends the use of two measures of community burden to determine the level of risk of transmission: 1) the total number of new cases per 100,000 persons in the past 7 days; and 2) the percentage of nucleic acid amplification tests (NAATs), including RT-PCR tests that are positive during the last 7 days. The two measures of community burden should be used to assess the incidence and spread of SARS-CoV-2 in the surrounding community (e.g., county) and not in the schools themselves.” The CDC provides a chart to assess whether the risk of transmission is low, moderate, substantial, or high. The CDC recommends different types of mitigations depending on the risk level. If the two indicators suggest different levels of risk, the mitigations recommended in the higher level of risk should be implemented, says CDC. The table below, reprinted from CDC’s report, provides CDC’s Indicators and Thresholds for Community Transmission of COVID-219.

 2/ Number of Cases per 100,000 Population. On July 1, a network of research, policy and public health experts convened by Harvard’s Global Health Institute and Edmond J. Safra Center published a Key Metrics for COVID Suppression framework that provides guidance to policy makers and the public on how to target and suppress COVID-19 more effectively across the nation. The targets for new COVID-19 cases per 100,000 people are as follows (these are converted from cases per day to cases per week): a) less than 7 cases: “on track for containment;” b) 7 to 63 cases: “community spread,” rigorous test and trace program advised; c) 70 to 168 cases: “accelerated spread,” stay-at-home orders and/or rigorous test and trace programs advised; and d) 169+: ”tipping point,” stay-at-home orders necessary.  The article is available here: https://globalepidemics.org/key-metrics-for-covid-suppression/

IDPH provides these categories and ratings: 1) “minimal” – fewer than 50 cases per 100,000 in a week; 2) “moderate” – between 50 and 100 cases per week; and 3) “substantial” more than 100 cases per 100,000 in a week.  In its Metrics for School Determination of Community Spread, IDPH says the “target” is 50 cases per week per 100,000 people.

3/ The Test Positivity Rate. In addition, on May 26, Johns Hopkins University & Medicine Coronavirus Resource Center said on its website that “the World Health Organization (WHO) advised governments [on May 15] that before reopening, rates of positivity in testing (i.e., out of all tests conducted, how many came back positive for COVID-19) should remain at 5% or lower for at least 14 days.”  Link: https://coronavirus.jhu.edu/testing/testing-positivity

The Harvard Global Health Institute (HGHI) says, “A network of research, policy, and public health organizations convened by Harvard and MIT called the TTSI Collaborative has agreed on a 3% test positive rate or below as a key indicator of progress towards suppression level testing.”

IDPH says the test positivity target is 5% or less. IDPH provides these categories and ratings: 1) “Minimal” – test positivity rate is equal to or less than 5%: 2) “Moderate” – test positivity rate is between 5% and 8%; and 3) “Substantial” – test positivity rate is over 8%. In its Metrics for School Determination of Community Spread, IDPH says the target is 5%.

4/ Calculations. The RoundTable calculates the number of cases per 100,000 using case data provided by IDPH and assuming that the population of Suburban Cook County is 2.469 million, that the population of Chicago is 2.710 million, and that the population of Illinois is 12.671 million.

5/ Northwestern University COVID-19 Cases. Ike C. Ogbo, Director of Evanston’s Health & Human Services Department, told the RoundTable that the COVID-19 cases reported by the City include cases of faculty, staff, and students attending Northwestern University who live in Evanston. The RoundTable asked the City in an FOIA Request to provide the number of NU students who tested positive for COVID-19 and who live in Evanston. The City refused to provide the data. On Oct. 26, the RoundTable appealed the City’s decision to the Public Access Counselor of the Attorney General’s Office. On Nov. 13, the City filed a response claiming it does not have any records showing the number of NU students who tested positive for COVID-19 and who live in Evanston.

The RoundTable has asked Northwestern University on several occasions to provide information breaking out the number of new COVID-19 cases of its faculty, staff and students by residency in Evanston. NU did not respond.

Larry Gavin

Larry Gavin was a co-founder of the Evanston RoundTable in 1998 and assisted in its conversion to a non-profit in 2021. He has received many journalism awards for his articles on education, housing and...