COVID-19 vaccines ramp up as more contagious U.K. variant gains ground

The rate of new COVID-19 infections continues to fall, and hospitalizations are now below 75,000 — a huge improvement from just a month ago. Infections with the B.1.1.7 (U.K.) variant, which is more contagious, are on the upswing, though. The Centers for Disease Control and Prevention (CDC) believes that the U.K. variant will be the dominant strain in the U.S. by next month. This makes masks and distancing all the more important until we get a huge portion of the population vaccinated.

COVID-19: Nationwide metrics

Metrics since April 1, 2020. Source: COVID-19 Tracking Project

Good news on the vaccine front

The U.S. administered two million doses of vaccine on February 11 alone. And so far, 35.7 million Americans have gotten at least one dose of vaccine, while 11.9 million have received both injections.

Rates are trending upward again but have varied recently due to distribution and weather-related hurdles

U.S. vaccination doses by day

In the U.S., the latest vaccination rate is 1,699,303 doses per day, on average. Source: Bloomberg

The CDC has just advised that those who have been vaccinated need not quarantine if they have a COVID-19 exposure if: 1) they had their second vaccine between two weeks and three months previously, and 2) have no symptoms. This could mean that contact tracing will lead to far fewer workplace exclusions if many workers have been vaccinated. I believe the limit of three months is based on limited experience with the vaccines and expect this will be extended in the future.

All the vaccines have proven highly effective at preventing serious disease, which keeps us from having overwhelmed hospitals and widespread death. Effectiveness against mild cases though is very important, as this means far fewer people will be spreading disease. Here’s a schematic from the University of Florida showing the importance of preventing all cases, not just cases with severe consequences.

All of the vaccine manufacturers are working on improvements that could increase effectiveness against the various strains, so I am hopeful we’ll have increasing vaccine efficacy despite the threat of mutations that can evade the vaccines.

Here, the same number of infections occur, but the consequences of these infections are systematically downgraded.

Vaccine that prevents disease but not infection

Cases with severe and moderate symptoms are reduced, while cases that are mild or asymptomatic increase. Source: The Economist

Here, the big difference is the reduction of overal infection or "R number" — the number of new infections to which each infection gives rise.

Vaccine that prevents disease and infection

Cases with severe and moderate symptoms are reduced, and mild or asymptomatic cases decrease as well. Source: The Economist

The CDC has released new guidance on mask wearing. Masks should fit tightly, have two to three layers and always cover the mouth and nose. They should not have valves. People should wear masks and follow social distancing guidelines when in public and should wash hands or use hand sanitizer after touching their masks. Employers whose employees are at the workplace should implement and communicate policies and procedures consistent with these new guidelines.

Masks have been shown to prevent spread of COVID-19 in barber shops and aboard airplanes. Communities with near-universal mask wearing have had substantial decreases in infections and less mortality. Masks were associated with a 79% decline in transmission in households where one person has COVID-19, and reduced risk of infection by 70% in a case-control study in Thailand and aboard the USS Theodore Roosevelt.

So, wear a mask!

Author

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Jeff Levin-Scherz, MD

Population Health Leader, Health and Benefits, North America

Jeff is a practicing physician and has led Willis Towers Watson’s clinical response to COVID-19. He has served in leadership roles in provider organizations and a health plan, and is an Assistant Professor at Harvard Chan School of Public Health.

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