Preventing overburdening of the healthcare system - still an important motto

A scientific update from the Swiss National Covid-19 Science Taskforce released in early August shows that the weekly number of vaccine doses administered in Switzerland has declined sharply since early June. Unless the vaccination rate can be increased again, 60% of the total population will not have received a first vaccination until the end of September, according to current expert forecasts. Vaccination campaign quo vadis?

Crucial to the potential burden of disease in the population and the potential burden on the health care system, he said, is the number of people in different age groups who lack immunity to SARS-CoV-2; this is especially true for the over-50 group [1]. Although about 50% of the Swiss population has already been fully vaccinated by Aug. 1, 2021 (Fig. 1), a large group of nonimmune individuals remains, so that the health care system may again be overburdened [2]. In the Federal Council’s three-phase model (protection, stabilization, normalization phase), the transition to phase 3 occurs at the time when all vaccine-eligible adults are fully vaccinated. At the moment, there are still at least as many people without immunity as already infected in Switzerland in every age group [1]. In the age groups up to 50 years, 2-3 times more people have no immunity than have been infected so far. In the age groups 50 and older, about the same number of people have no immunity as have been infected so far.

Increasing vaccination coverage remains a priority

“If a large proportion of currently unimmune people were infected, the expected cumulative burden of disease would be similar to or greater than the total burden of disease in the pandemic so far,” according to a Swiss National Covid-19 Science forecast 03/08/21 [1]. The increase in the number of vaccinated persons therefore continues to have the highest priority, because a further increase in the number of cases must be expected due to the more infectious delta variant and the significantly less stringent measures (BAG, 28.07.21) [2]. Compared to other countries in Western and Southwestern Europe, both the vaccination rate and coverage are lower in Switzerland. For example, in the United Kingdom and Spain, the percentage of people over 70 years of age who are not dually vaccinated is only about 2% [3] and 3%, respectively [4], whereas in Switzerland it is about 17% [5]. Among the over-50s – the age group that is particularly relevant for hospitalizations – the proportion of unduplicated vaccinees in the UK is less than 5%, while in Switzerland it is many times higher [1,3]. In contrast, vaccination coverage for other infectious diseases in Switzerland is high by European standards [6]. From this, the authors of the Science Taskforce conclude that the observed difference in Covid 19 vaccination rates and coverage between Switzerland and other Western European countries does not arise from a fundamental cultural or organizational difference, but can be narrowed by increased efforts [1].

How can vaccination skepticism be countered?

A data analysis based on the FORS COVID-19 MOSAiCH survey conducted a few months ago shows that, at approximately 22%, a substantial proportion of the 1245 individuals surveyed* were critical of vaccination at that time [15,16]. In the United Kingdom and Spain – both countries where, as mentioned, Covid 19 vaccination coverage is very high among people over 50 years of age – people over a certain age are contacted directly and personally by local health workers or are sent an invitation to be vaccinated by the national health authority. The authors of the Swiss National Covid-19 Science Taskforce suggest that this strategy should also be applied in Switzerland. To communicate the importance of vaccination, the following arguments may be helpful [1]:

The two vaccines offered in Switzerland provide excellent protection against severe disease and death.
Most cases of illness and hospitalization with Covid-19 in Switzerland and abroad occur in the unvaccinated.
Unvaccinated people are at higher risk of contracting SARS-CoV-2 and transmitting the virus to others.
Vaccination is the most effective measure to protect oneself and others, including health care workers, and thus jobs and the economy as a whole.

* 1245 respondents participated in the third round of the Covid-19 supplemental survey, which was conducted as part of the annual MOSAiCH social science survey between mid-March and mid-April 2021. The results were statistically weighted to achieve better representativeness for the Swiss population [15,16].

Although breakthrough infections can occur, they account for only a small percentage of new cases and the majority are mild. The vast majority of vaccinated people are thus protected from serious illness and death, unlike the unvaccinated.

Experience shows that different measures must be combined for an effective vaccination campaign [7]. Among other measures, direct incentives and rewards are also used in various countries to increase vaccination coverage.

How dangerous is the delta variant?

Since calendar week 26, Delta (B.1.617.2) has been the dominant variant in Switzerland. This variant, originally described in India, had a frequency of 1% at calendar week 19, a frequency of 24% at calendar week 24, and a frequency of 98% at calendar week 29 among sequenced cases [8]. Due to delays in recording the sequences, these frequencies may still change, especially in calendar week 29. From this increase in the frequency of delta, one can calculate a transmission advantage over alpha of 67-75% [8]. Delta appears to cause more severe courses than the previously dominant strains in Switzerland. Data from Scotland [9] suggest that infection with delta is about twice as likely to result in hospitalization as infection with alpha (hazard ratio 1.39-2.47). Data from Canada show a 120% (93-153%) increase in hospitalization risk over strains circulating in 2020 [1,10]. Vaccine protection against infection and symptomatic disease appears to be reduced in Delta. A new report from the CDC indicates that Delta can infect fully vaccinated people with relevant frequency [17]. Studies quantifying the efficacy of mRNA vaccines against infection are ongoing. Efficacy against infection of Pfizer/BioNtech’s vaccine is 39% (9-59%) according to data from Israel [11] and 79% (75-82%) according to data from Scotland [9]. Data from Israel also suggest that the effectiveness of vaccination against symptomatic infections is 40.5% (8.7-61.2%) [11]. Data from England suggest 79% (78-80%) [12] and data from Canada suggest 85% (78-89%) [13] (Pfizer/BioNtech and Moderna). So far, it is unclear why efficacy seems to be lower in Israel than in other countries: Declining vaccine efficacy in early vaccinated individuals in Israel, different vaccines (in Canada, Moderna in addition to Pfizer/BioNtech), or the prolonged time interval between the two vaccinations (especially in the UK) could play a role. Importantly, however, an efficacy of 40% against infection still means that 4 in 10 infections can be prevented and thus transmission dynamics are still slowed by vaccination [1].

Literature:

Swiss National Covid-19 Science Taskforce, 3.8.21, https://sciencetaskforce.ch/wissenschaftliches-update-3-august-2021 (last accessed 06.08.21).
FOPH: Information to the cantons and the social partners regarding the planned consultation at the end of July 2021 Document dated 28 July 2021 for information to the cantons and the social partners, www.bag.admin.ch/bag/de/home/ krankheiten/ausbrueche-epidemien-pandemien (last retrieved 06.08.21)
Office for National Statistics: Coronavirus (COVID-19) Infection Survey, antibody and vaccination data, UK: 21 July 2021. www.ons.gov.uk/peoplepopulationandcommunity/healthandsocialcare/conditionsanddiseases/bulletins (last accessed 06.08.21)
Gobierno de Espana, www.mscbs.gob.es/profesionales/saludPublica/ccayes/alertasActual/nCov/documentos/Informe_GIV_comunicacion_20210630.pdf, (last accessed 06.08.21).
BAG: www.covid19.admin.ch/en/vaccination (last accessed 06.08.21)
Swiss National Covid-19 Science Taskforce, 7/20/21, https://sciencetaskforce.ch/en/scientific-update-of-20-july-2021 (last accessed 08/06/21).
Wood S, Schulman K: N Engl J Med 2021; 384: e23.
covSPECTRUM, https://cov-spectrum.ethz.ch (last accessed 08/06/21).
Sheikh A, et al: The Lancet 2021; 397(10293): 2461-2462.
Fisman DN, Tuite AR : Progressive Increase in Virulence of Novel SARS-CoV-2 Variants in Ontario, Canada, www.medrxiv.org/content/10.1101/2021.07.05.21260050v2 (last accessed 08/06/21.
gov.il, www.gov.il/BlobFolder/reports/vaccine-efficacy-safety-follow-up-committee/he/files_publications_corona_two-dose-vaccination-data.pdf (last accessed 06.08.21).
Public Health England, https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1007376/Vaccine_surveillance_report_-_week_30.pdf (last accessed 06.08.21).
COVID-19 Alberta statistics, www.alberta.ca/stats/covid-19-alberta-statistics.htm#vaccine-outcomes (last accessed 06.08.21).
FOPH: “Medium-Term Planning Concept Paper,” 06/30/2021, www.bag.admin.ch/bag/de/home/krankheiten/ausbrueche-epidemien-pandemien/aktuelle-ausbrueche-epidemien/novel-cov/situation-schweiz-und-international.html, (last accessed 08/06/21).
Monsch G-A, Nisple K, Steinmetz S: Vaccination readiness in Switzerland: who wants, who does not, and for what reasons. www.defacto.expert/2021/07/08/die-impfbereitschaft-in-der-schweiz-wer-will-wer-nicht-will-und-aus-welchen-gruenden (last accessed 06.08.2021)
FORS, https://forscenter.ch/projekte/fors-covid-19-erhebungen/?lang=de (last accessed Aug. 06, 2021).
CDC, Morbidity and Mortality Weekly Report (MMWR), www.cdc.gov/mmwr/volumes/70/wr/mm7031e2.htm?s_cid=mm7031e2_w, (last accessed Aug. 06, 2021).