Healthcare worker wearing PPE (personal protective equipment)
In December 2020, when the majority of the United States was seeing its worst surge in Covid-19 cases, hospitalizations and deaths, Covid-19 vaccinations were made available to healthcare workers. A report in this week’s New England Journal of Medicine presents data on vaccinations and Covid-19 infections in University of California San Diego (UCSD) healthcare employees between December 2020 and July 2021. Their findings are in keeping with what we’ve been seeing: the combination of now recognized waning immunity, reduced mitigation measures such as masking, the arrival of the increasingly transmissible delta variant, and slowing in vaccination rates have translated to rises in cases, even in vaccinated individuals. Including those taking care of you.
The group reviewed information from approximately 19,000 adult employees from both the UCSD Health and the UCSD Health Sciences Systems which included hospital and clinic staff (approximately 11,000 individuals) and faculty and staff at the schools of medicine, pharmacy and public health (approximately 8,000 individuals). By March 2021, over 76% of the workforce was fully vaccinated, and by July 2021 it was up to 83%. The University of California mandated that by July 15, 2021 all personnel, trainees and students upload proof of vaccination.
Signage for a Covid-19 vaccination site run by UC San Diego Health on the University of California ... [+]
Beginning with the early months of the pandemic, the UCSD Health system has been monitoring its students and employees for Covid-19 symptoms with daily health screenings, and has had a low threshold for SARS-CoV-2 PCR testing if there was either one symptom on the daily tracker, or self-reporting of a history of exposure to an infected individual. By February 2021, case numbers in this population plummeted. Between March and June 2021, there were fewer than 30 positive Covid-19 cases per month in this group of 19,000.
But as perfect storms can cause perfect disasters, so things went in San Diego, as well as in many healthcare institutions throughout the country. On June 15, 2021, indoor mask mandates for vaccinated individuals were lifted, daily vaccinations dropped substantially, and the highly infectious delta variant reared its ugly head, even in vaccinated airways.
A joint Government and NHS public information display indicates that a Covid-19 Variant of Concern ... [+]
The authors of the study, who reviewed 227 positive Covid-19 cases between March 1, 2021 and July 31, 2021 found that 130 of these were in fully vaccinated workers, and 109 of 130 demonstrated at least one symptom related to Covid-19. There were 90 un-vaccinated workers who tested positive (80 of these had at least one symptom), and 7 who tested positive were partially vaccinated. There were no deaths, and there was one hospitalization in an un-vaccinated worker. The authors calculated vaccine effectiveness over time based on these numbers, and found that the effectiveness was over 90% between March and June 2021, but fell to below 65% in July 2021. Those who had been vaccinated in January or February were twice as likely (6.7 per 1,000 people) to test positive than those who were vaccinated in March through May (3.7 per 1,000 people). Those who were un-vaccinated were three to six times more likely to become infected in July 2021 than those in both vaccinated groups (16.4 per 1,000 people).
Covid nasal PCR testing(Photo by Leon Neal/Getty Images)
As we continue to learn over and over again, protection from SARS-CoV-2 infections necessitates layers of prevention. Increased vaccination in the general public, especially in the setting of more infectious variants, continued masking, and symptom monitoring remain vital. Isolation if exposed and/or if symptoms present are also necessary, as well as frequent testing.
The issue of a third dose is now front and center, with over 1 million people in the U.S. having received a third dose to date. This is currently recommended only in immunocompromised individuals, such as those receiving cancer chemotherapy, or other medications weakening one’s immune system such as those necessary after organ transplantation. In addition, those with chronic illnesses or conditions leading to weakened immune function are considered immunocompromised as well. But with many healthcare professionals and older adults hitting the eight month mark since their second dose, millions more will likely be headed to dose three in the coming weeks.
