COVID-19 vaccine protection, primary care delays and international differences during the pandemic

The COVID-19 vaccines' protective effects against the delta and omicron variants were quantified by an analysis of 422,966 COVID-19 infections in Los Angeles County, published by MMWR on Feb. 1. From Nov. 7, 2021, to Jan. 8, 2022, case and hospitalization rates were highest among unvaccinated people and lowest in those who had received a booster. During omicron predominance, infection and hospitalization rates among unvaccinated people were 3.6 and 23.0 times those in boosted people, and 2.0 and 5.3 times those in people who were fully vaccinated with no booster. Another study, published by JAMA on Feb. 3, looked at the prevalence of SARS-CoV-2 antibodies among 1,580 unvaccinated U.S. adults in fall 2021, finding antibodies in 99% of those who reported having tested positive for COVID-19, 55% who believed they had COVID-19 but were never tested, and 11% who believed they hadn't had COVID-19.

Two recent studies looked at delays in primary care during the pandemic. Of 3,257 Americans ages 70 years or older who were surveyed in 2020, 38.0% reported delayed care, including 20.2% from a dentist, 18.6% from their usual doctor, and 15.6% from a specialist. The most common reason for delayed care was that the clinician canceled, closed, or suggested rescheduling, according to results published by the Journal of General Internal Medicine on Jan. 31. Similarly, a study of one health system, published by the same journal on Jan. 26, found significant decreases in health screenings in March to May 2020 compared to earlier in the year. In May to July 2020, rates went back up, but not to their original levels, except for diabetic nephropathy monitoring. The authors concluded that “it is important for health care providers to develop strategies to continue providing the best care to their patients, even if they are unable to come to the clinic.”

Several factors, but not pandemic preparedness, were associated with international variation in COVID-19 infection and mortality rates, according to a study published by The Lancet on Feb. 1. The study used data from 177 countries and territories between Jan 1, 2020, and Sept 30, 2021, and found that COVID-19 mortality rates were associated with countries' average age and body mass index and gross domestic product per capita. Countries at higher elevations and those with more seasonality in weather had higher infection rates, while those with higher trust in government and other people had lower rates. “A high ranking on the leading measures of health system capacity and pandemic preparedness has not only been insufficient for success in this pandemic, but also unnecessary,” observed the authors. “Governments should invest in risk communication and community engagement strategies to boost the confidence that individuals have in government guidance in public health crises, especially in settings with historically low levels of government and interpersonal trust.”