Quick Take: USCD Hospital Worker COVID19 Correspondence From NEJM

Over the past 24 hours, the New England Journal of Medicine published a correspondence letter from researchers at the University of California, San Diego title “Resurgence of SARS-CoV-2 Infection in a Highly Vaccinated Health System Workforce” [1]. In this letter the authors report that by March 2021, 76% of their healthcare staff was fully vaccinated, and by July, they reached an 83% vaccination rate for their workforce. They collected data using only workers that demonstrated at least one symptom during daily screening, and that had a positive COVID19 PCR test across both vaccinated and unvaccinated people.

This method cultivated in the figure below that I would describe as cathartic for those who are in the unvaccinated crowd out there.

 

We can see that the rate of the symptomatic vaccinated workers has increased by a much sharper degree than the unvaccinated. In fact, according to the table from the article below, the vaccinated group only made up 19% - 33% of symptomatic cases until July. In July, they made up 75% of all the symptomatic cases reported.

Along the way, the authors have been calculating the vaccine effectiveness rate based on the differences between the unvaccinated group and the vaccinated group as shown in the bottom part of the table (the approximation of the math is 100 – [(Vaccinated attack rate)/unvaccinated attack rate) * 100). By July, the effectiveness of the vaccines drop to a dismal 65%.

The author’s conclusion:

“The dramatic change in vaccine effectiveness from June to July is likely to be due to both the emergence of the delta variant and waning immunity over time, compounded by the end of masking requirements in California and the resulting greater risk of exposure in the community.”

However, I’ll add that there are other reasons to explain this sudden shift in the vaccinated becoming more and more likely to get sick than the unvaccinated.

Archo’s Additions: 

1.    False security theory. The vaccinated workers are less likely to be careful about the use of preventative measures. Invincibility complexes are easy to achieve since the much of the messaging about the vaccines until now have been "you can go back to normal." [2,3]

2.     Business practice theory. It's possible that University of California, San Diego knows who is and is not vaccinated. They may be "sidelining" unvaccinated workers because of their status and as a byproduct increases the exposure for the vaccinated workers, leading them to be infected more.

3.    Immunity disparity theory. If we assume that both groups have similar exposure to COVID19 patients, but the vaccinated group have mostly monoclonal (single type) antibodies against spike protein. Meanwhile the unvaccinated could have mostly polyclonal (many type) antibodies against the spike protein they were exposed to while working since they weren't trained by the vaccine for their immune response [4].

4.    False pretense theory. The data on the effectiveness of the vaccines against Delta variant was even worse than we thought. Keep in mind Moderna claimed their vaccine was highly effective against delta based on a study of only 8 people [5,6]. Meanwhile, Pfizer-BioNTech claimed that their vaccine was 88% effective against the delta strain based on a study they submitted to the New England Journal of Medicine [7].

References:

[1] Keehner J, Horton LE, Binkin NJ, et al. Resurgence of SARS-CoV-2 Infection in a Highly Vaccinated Health System Workforce. New England Journal of Medicine. 2021;0:null.

[2]  “Go get the shot”: Biden highlights path back to normal [Internet]. AP NEWS. 2021 [cited 2021 Sep 3]. Available from: https://apnews.com/article/pandemics-health-joe-biden-business-government-and-politics-3d38206bc38f012b9598154b59d27d1f.

[3]  CDC Says Vaccinated People Can Go Back to Normal Life | Voice of America - English [Internet]. [cited 2021 Sep 3]. Available from: https://www.voanews.com/covid-19-pandemic/cdc-says-vaccinated-people-can-go-back-normal-life.

[4]  Lipman NS, Jackson LR, Trudel LJ, et al. Monoclonal Versus Polyclonal Antibodies: Distinguishing Characteristics, Applications, and Information Resources. ILAR Journal. 2005;46:258–268.

[5]  Reuters. Moderna’s COVID-19 vaccine shows promise against Delta variant in lab study. Reuters [Internet]. 2021 Jun 29 [cited 2021 Sep 3]; Available from: https://www.reuters.com/business/healthcare-pharmaceuticals/modernas-covid-19-vaccine-shows-promise-against-delta-variant-lab-study-2021-06-29/.

[6]  Choi A, Koch M, Wu K, et al. Serum Neutralizing Activity of mRNA-1273 against SARS-CoV-2 Variants [Internet]. 2021 [cited 2021 Sep 3]. p. 2021.06.28.449914. Available from: https://www.biorxiv.org/content/10.1101/2021.06.28.449914v1.

[7]  Lopez Bernal J, Andrews N, Gower C, et al. Effectiveness of Covid-19 Vaccines against the B.1.617.2 (Delta) Variant. New England Journal of Medicine. 2021;385:585–594.