The Latest in Covid-19 News

 Last Friday by the CDC released a report on the vaccine protection after 2 doses of mRNA vaccine after two and three doses. A waning of vaccine protection after two doses observed during the period when the delta variant predominated had prompted CDC to recommend that all persons older than 12 years receive a booster dose of COVID-19 mRNA vaccine 5 months or more after completion of a primary mRNA vaccination series and that immunocompromised persons receive a third primary dose.

This study was done during the period of the Covid variant predominance moved from the Delta to the Omicron and is a preliminary look at the effectiveness of the booster regime for the mRNA vaccines.

The CDC used data from emergency department/ urgent care visits and hospitalizations among U.S. adults aged ≥18 years at various time points after receipt of a second or third vaccine dose. A weakness in the data is that people who received 3 doses included those who received a third dose in a primary series because they were immunocompromised or high risk and a third dose as booster dose after a 2 dose primary series.

Among 241,204 encounters of people with COVID-19 like illness seeking care, 185,652 (77%) and 55,552 (23%) occurred during the Delta- and Omicron predominant periods, respectively. Among the people 46% were unvaccinated, 44% had received 2 doses of vaccine, and 10% had received 3 doses.

During the Delta-predominant period, vaccine effectiveness was higher after receiving a third dose than after a second dose; however, vaccine effectiveness declined with increasing time since vaccination. Among recipients of 3 doses, vaccine effectiveness was 97% within 2 months of vaccination and declined to 89% among those vaccinated ≥4 months earlier.

However, the effectiveness of the mRNA vaccines against Omicron was vastly different. During the Omicron-predominant period, vaccine effectiveness at preventing COVID-19 was lower overall compared with that during the Delta-predominant period and waned much faster after the second dose, from 69% within 2 months of vaccination to 37% at ≥5 months after vaccination.

Though during the Omicron-predominant period, mRNA vaccination was still highly effective against more severe disease. When looking only at COVID-19–associated emergency department/ urgent care visits and hospitalization for Covid-19 vaccine effectiveness was 87% and vaccine effectiveness against hospitalizations for COVID-19 vaccine effectiveness was 91% within 2 months after a third dose. Once more effectiveness waned, declining to 66% for prevention of COVID-19 emergency department/ urgent care visits by the fourth month after receipt of a third dose and to 78% for hospitalizations by the fourth month after receipt of a third dose. The finding of lower vaccine effectiveness for 2 or 3 doses during the Omicron-predominant period is consistent with previous reports and studies in Israel.

Right now the greater concern in our society is the rising mental-health problems, drug overdoses, violent crime, loss of learning and harm to our children. We need to turn the focus to protecting the young. As David Leonhardt of the New York Times pointed out over the weekend “At this point in the pandemic, there is a strong argument that a targeted approach — lifting restrictions while taking specific measures to protect the vulnerable — can maximize public health. ...” Read David Leonhardt’s newsletter here. 

As a final note, yesterday, Governor Glenn Youngkin signed SB739, which allows a parental opt-out from local school mask mandates and ensures five day a week in-person instruction. The change will take effect after a transition period by March 1, 2022.