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March 5th, 2021 – Vaccines, Immunity, Variants, and Schools


Cases of COVID-19 across the globe are in flux. The U.S. case counts have stopped falling and have flattened, while cases in some areas of Europe (France and Italy) as well as Brazil are increasing, and others (U.K., Spain) continue to decrease. Vaccines remain the topic of interest and this week brought a new vaccine and more details regarding vaccination of people who have recovered from COVID-19. In addition, there are some interesting updates for schools.

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Be Safe,


1) Vaccinating Those Who Have Recovered

A study published in the journal Lancet last week adds to the growing body of evidence regarding people who have recovered from COVID and their response to a vaccine. This small study of 51 people tested the anti-S (spike) antibody titers of healthcare workers. Half had previously recovered from COVID. Interestingly, the antibody results reported showed the following:

  • Never infected and one dose Pfizer vaccine = same antibody levels as someone who has recovered form infection.
  • Never infected and two doses Pfizer vaccine = same antibody level as someone who has recovered and one dose vaccine.

After finding that recovered patients have a very high antibody response with one vaccine dose (Pfizer), they concluded that a single dose was sufficient for this population.

A second study, also in the journal Lancet last week, similarly examined 72 healthcare workers who received the Pfizer vaccine. They studied antibody AND T cell response. They found :

  • Those with prior infection mounted a much higher antibody response after a single dose of vaccine.
  • The antibody response in people who had never been infected (naive) was not as robust after age 50. 10 participants, all over 50, had either low response or no response to a single Pfizer dose.
  • T cell response was vigorous in those who had recovered and then received a single vaccine dose.
  • T cell response was low in uninfected (naive) people who received a single vaccine dose.

This study concluded that countries recommending delaying the second dose of the vaccine take into account the patient’s age, as age 50 was associated with a less robust response to a single dose. They also use this evidence to recommend continued mask use after vaccination.

Lastly, a third study appearing in JAMA also reached a similar conclusion. They studied the response of 59 healthcare workers after receiving either the Moderna or Pfizer vaccine. Once again, those with prior infection showed a larger antibody response to a single dose. They concluded that patients who have recovered from COVID require only one dose OR should moved down the priority list for vaccination.

It remains unknown if those who recover from COVID need a vaccine at all, or if the vaccines aid in protection from variants. But these studies add to the growing body of evidence suggesting only one dose is needed for those who have recovered. (Previous similar articles discussed in the Feb 26th newsletter , item 6; and Feb 12th newsletter , item 4)

2)Variants and T Cells

In addition to antibodies, T-cells play an important role in immunity. A study published online and not yet peer reviewed, examined T-cell response to multiple variants of the SARS-CoV-2 virus. They included B.1.1.7 (U.K.), B.1.351 (South Africa), P.1 (Brazil) , and CAL.20C (California) as well as recipients of the Moderna or Pfizer vaccines. They found that the variants had no effect on T-cell response in people who have recovered from infection or those who have received a vaccine. Though this was a small study using the plasma of 30 volunteers, it is certainly great news. I hope the study is found to be sound after review, and that more articles will come to similar conclusions. If this study’s findings are reproducible, then those who have recovered from COVID or received vaccination will have immunity to the multiple variants currently in circulation.

3) The New York Variant

A study published online and not yet peer reviewed, details the emergence of the B1.526 variant. It was first detected in New York State in December 2020. According to the study, samples containing this variant increased until the study ended in February 2021. Samples from nearby states in the Northeast U.S. also contained the variant suggesting spread in other areas as well. The clinical significance of this variant (how easy it is spread, lethality compared to other strains) remains unknown.

4) The P1 (Brazil) Variant

An article appeared in the New York Times discussing the emergence and effects of the P1 variant in Brazil. It cites three studies that examined the variant and contains an interview with one of the study authors. The article states this variant first appeared in November 2020 and caused the corresponding increase in cases. The article’s title “Virus Variant in Brazil Infected Many Who Had Already Recovered From Covid-19” suggests that this variant caused a sudden increase in cases by reinfecting a large portion of the population. However, the only evidence presented is that blood samples from people who had previously been infected had antibodies that were less effective against the P1 variant. The study author concludes that this may mean that people could have become reinfected causing the second large increase in cases in the country. However, this is only a theory. Similar large “waves” of infection have been seen in the U.K. and the U.S. without evidence for high numbers of reinfection. Reinfection continues to be a rare occurrence.

5) AstraZeneca and Pfizer single dose performance

A new study from Public Health England examined people after receiving the first dose of the Pfizer vaccine or the AstraZeneca vaccine. They found:

  • Both are “are highly effective in reducing COVID-19 infections among older people aged 70 years and over”
  • 4 weeks after one dose of the Pfizer vaccine, protection was estimated at 57-61%
  • 4 weeks after one dose of the Oxford-AstraZeneca vaccine, protection was estimated at 60-73%
  • 4 weeks after one dose of either vaccine in patients over 80 years old, protection was estimated to be >80%
  • The Pfizer vaccine leads to an 83% reduction in deaths from COVID-19.

Once again, this is welcome news regarding the performance of just one dose of vaccine. In countries where efforts are focused on getting a first dose to as many people as possible, this data suggests the practice is safe and efficacious. This seems contrary to the lab study reported in section 1 above which demonstrated a reduced immune response in patients over age 50 receiving only one dose. However, it highlights the difference between laboratory serum testing against viruses and clinical data based on actual patient outcomes.

6) CDC Ventilation Guidelines For Schools

Last week, the CDC published a new page titled “Ventilation in Schools and Childcare Programs”. It details the steps schools can take to improve indoor ventilation. Though the page is new, the recommendations are similar to what has been recommended by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) since the summer of 2020. Overall. these guidelines emphasize the need for continuous ventilation indoors and provide some easy ways to improve air filtration. They also stress the value of outdoor air.

7) Clusters of Elementary School Outbreaks in Georgia

Last week the CDC published the results of an investigation into a cluster of outbreaks in elementary schools in Cobb County, Georgia that occurred between December 2020 and January 2021. The report details 9 clusters of outbreaks in 6 schools, with 13 educators and 32 students becoming infected. Some interesting findings from the investigation included:

  • 2 clusters were responsible for almost half of all cases. These two were thought to be due to educator to educator transmission, followed by educator to student transmission.
  • All 9 clusters had “less than ideal distancing”. Physical distancing of >6 ft was not possible because of the high number of in-person students and classroom layouts.
  • 5 clusters had inadequate mask use by students, which was determined by interviews. This occurred even though the school district mandated in-classroom mask use except while eating, and both reported and observed compliance during site visits was high.
  • Only 60% of exposed close contacts received testing, the remaining 40% declined or could not be reached.
  • Although plastic dividers were placed on desks between students, students sat <3 ft apart.

Overall, the CDC concluded that “Consistent with findings from international studies, this report found that initial infections among educators played a substantial role in in-school SARS-CoV-2 transmission and subsequent chains of infection to other educators, students, and households, highlighting the importance of preventing infections among educators in particular”. The investigation supports the early vaccination of teachers in order to prevent in-school transmission.

8) Texas and Mississippi cease mask mandates

The governor of Texas is lifting the statewide mandate for masks and allowing businesses to open at 100% capacity starting March 10th. Similarly, The governor of Mississippi made a similar announcement lifting all mask mandates and opening businesses to 100% capacity beginning March 3rd. However, restrictions on schools and arenas remain.

9) Vaccine Reviews and Authorization

Late last week, the FDA authorized emergency use of the Johnson and Johnson vaccine. The Learn EM review of the Johnson and Johnson vaccine, based on the data submitted to the FDA, was published this past Monday. Unlike previous vaccine trials, SARS-CoV-2 variants were known and are still being sequenced from the phase 3 trial participants. Participating countries included:

  • Argentina 6.8%
  • Brazil 16.6%
  • Chile 2.6%
  • Colombia 9.7%
  • Mexico 1.1%
  • Peru 4.0%
  • United States 44.1%
  • South Africa 15.0%

The variants sequenced so far include:

  • Wuhan-H1 variant D614G in the U.S. (96.4% of sequenced cases)
  • B.1.351 in South Africa (94.5% of sequenced cases)
  • P.2 lineage in Brazil (69.4% of sequenced cases, with the remaining 30.6% Wuhan-H1 variant)
  • No cases identified of B.1.1.7 (U.K) or P1 (Brazil) lineages as of February 12, 2021

For more details about how the vaccine performed and the populations studied, see the Learn EM review. In addition, similar reviews of the Moderna and Pfizer vaccines were published late last year.

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