Vaccines

(last update 26 May 2021)

Availability of COVID-19 vaccines in the EU/EEA

As of April 2021, four COVID-19 vaccines have received conditional marketing authorisation in the EU/EEA, following evaluation by European Medicines Agency (EMA), and are part of the EU Coronavirus Vaccines Strategy Portfolio: Comirnaty (BNT162b2) developed by BioNTech/Pfizer, COVID-19 Vaccine Moderna (mRNA-1273), Vaxzevria (previously COVID-19 Vaccine AstraZeneca) (AZD1222), and COVID-19 Vaccine Janssen (Ad26.COV 2.5).

EMA has initiated rolling reviews for the following COVID‑19 vaccines: NVX-CoV2373 developed by Novavax (rolling review started on 3 February 2021), CVnCoV by Curevac (rolling review started on 12 February 2021), Sputnik V (Gam-COVID-Vac) by Gamaleya (rolling review started  on 4 March 2021) and COVID-19 Vaccine (Vero Cell) Inactivated by Sinovac Life Sciences Co., Ltd (rolling review started on 4 May 2021) [1]. A monitoring system to collect information on the vaccine roll-out, including information on the number of vaccine doses distributed to countries by the manufacturers and the number of doses administered to individuals by age group/other priority groups may be viewed on the COVID-19 vaccine tracker on ECDC’s website.

Efficacy, effectiveness and safety - EU/EEA authorised COVID-19 vaccines

COVID-19 vaccine efficacy from clinical trials

COVID-19 vaccines licensed for use in the EU/EEA have been shown during clinical trials to be highly effective in providing protection against symptomatic COVID-19 and severe disease. Table 1 shows the overall vaccine efficacy of the licensed vaccines after completed vaccination.

Table 1. Overall efficacy of COVID-19 vaccines authorised for use in the EU

Vaccine name Overall % vaccine efficacy Date of study launch and data cut-off for primary analysis of efficacy
Comirnaty# 95.0% (95% CI 90.3, 97.6) (≥16 years) (against COVID-19) [2] 27 July 2020–9 October 2020
COVID-19 Vaccine Moderna# 94.1% (95% CI 89.3,96.8) (≥18 years) (against COVID-19 illness regardless of severity) [3] 27 July 2020–21 November 2020
Vaxzevria#

61.2% (95% CI 41.0,75.7) (≥18 years) (against COVID-19 with two standard doses)

90.0% (95% CI 67.4-97.0) (against COVID-19 with a low dose followed by a standard dose)

70.4% (95.8% 54.8-80.6) (overall vaccine efficacy against COVID-19 across both dosing groups) [4]

23 April 2020–4 November 2020
COVID-19 Vaccine Janssen*

66.9% (95% CI 59.03, 73.40) (≥18 years) (against COVID-19 of any severity)

76.7% (95% CI 54.6 to 89.1) (against severe-critical COVID-19) [5]

21 September 2020–22 January 2021

 

#two-dose schedule

*one-dose schedule

Note: trial end points, study populations and follow-ups differed between the trials. Also, differing incidence of SARS-CoV-2 infection in the population and the prevalence of SARS-CoV-2 variants of concern circulating at the time of the trials may also have an effect on efficacy results.

COVID-19 vaccine effectiveness - real-world evidence

Since the approval of the first COVID-19 vaccine in the EU/EEA, the body of evidence regarding vaccine effectiveness and population impact has been increasing. Evidence from real-world usage of COVID-19 vaccines has confirmed the clinical trial findings and also showed high vaccine effectiveness against PCR-confirmed SARS-CoV-2 infection [6]. Antibody titres in vaccinated individuals peak at 3−4 weeks following vaccination. However, follow-up periods for vaccinated persons are not yet  long enough to draw conclusions on the duration of protection against infection or disease in the long term [7]. There is limited information on duration of immunity post-vaccination, either generally or for individuals of different ages and with underlying comorbidities, which might also vary by vaccine product.

ECDC recently published a technical report reviewing evidence (up to 29 March 2021) on immunity and possibilities for transmission from infected, previously-vaccinated individuals to susceptible contacts [8]. Direct evidence is beginning to emerge on the impact of vaccination on transmission risk. A large register-based study on prevention of COVID-19 transmission in households of vaccinated healthcare workers from Scotland suggests that vaccination of a household member reduces the risk of infection in susceptible household members by at least 30% [9]. A recent study examining the impact of vaccination on household transmission in England found that the likelihood of household transmission is 40−50% lower for households where the index cases were vaccinated 21 days or more prior to testing positive (compared to no vaccination). The effects are similar for Comirnaty and Vaxzevria vaccines [10]. There is evidence that vaccination significantly reduces viral load and symptomatic/asymptomatic infections in vaccinated individuals [11] which could translate into reduced transmission, although the vaccine efficacy varies by vaccine product and target group.

One factor that will modulate the risk of transmission include the ability of an individual to mount an immune response post-vaccination (i.e. immunocompromised individuals may not mount an immune response and the immune response may be lower in older and frail adults). Another factor is the length of time since vaccination, given that there has been no long-term follow up on duration of immunity as yet, since COVID-19 vaccines only recently became available.

In light of the accumulating evidence, the total number of infections is expected to decrease significantly as vaccination coverage increases, provided that there is a match between the vaccine strains and the circulating virus strains. This will lead to decreased transmission overall. With no vaccine reaching 100% efficacy or providing sterilising immunity, a certain number of fully-vaccinated individuals will remain susceptible and become infected if exposed to the virus. Emerging evidence from real-world studies indicates that breakthrough infections occur to the extent expected, based on results from clinical trials and subsequent observational studies.

Given that COVID-19 vaccines are being deployed throughout the EU, discussions are now ongoing regarding exemptions or relaxation of measures for fully-vaccinated individuals. Some EU/EEA Member States have already taken measures to exempt fully-vaccinated individuals from some of the requirements which apply to the general population. ECDC recently published interim guidance on the benefits of full vaccination against COVID-19 in relation to transmission and the implications for non-pharmaceutical interventions [6]. This document provides a risk analysis of:

  • the risk that a fully-vaccinated individual will develop severe COVID-19 disease, and
  • the risk that an unvaccinated individual in contact with a fully-vaccinated person exposed to SARS-CoV-2 infection will develop severe COVID-19.

Risk of infection and onward transmission of SARS-COV-2 in fully vaccinated individuals should not be considered in isolation, but always assessed against a broader epidemiological context. Experiences from Israel and the UK clearly show that with an increasing vaccination coverage in the population, there are stronger signs of indirect protection and further relaxation of measures may eventually become possible for fully-vaccinated individuals.

COVID-19 vaccine safety

The four EU/EEA authorised COVID-19 vaccines all showed a very good safety profile in clinical trials before receiving approval from the European Medicines Agency (EMA). Since licensing, EMA, other regulatory agencies and international bodies have been continuously monitoring the safety of COVID-19 vaccines.

In March 2021, following the notification of cases of blood clots with low blood platelets in people who had received Vaxzevria, the Pharmacovigilance Risk Assessment Committee (PRAC) of EMA initiated a detailed review of safety data on cases of thromboembolic events received through the EUDRAVIGILANCE database. In April 2021, PRAC concluded that thromboembolic events associated with thrombocytopenia are a very rare side effect of Vaxzevria [12]. Based on a review of data on vaccination and disease epidemiology, EMA’s Committee for Medicinal Products for Human Use (CHMP) concluded that the benefits of vaccination in terms of averted hospitalisations, ICU admissions and deaths rise as age and infection rates increase. EMA stated that even though very rare cases of blood clots with low blood platelets have occurred following vaccination, the benefits of Vaxzevria outweigh its risks in adults of all age groups. EMA recommendations fora second dose of Vaxzevria remain in line with the product information (i.e. 4−12 weeks interval) [13].

In April 2021, the US Food and Drug Administration and the US Centers for Disease Control and Prevention [14] recommended that the use of the Janssen COVID-19 vaccine be paused in the US while they investigate reports of a blood clotting disorder in six vaccine recipients who developed cerebral venous sinus thrombosis in combination with low levels of blood platelets (thrombocytopenia). At the EMA PRAC meeting on 20 April 2021, it was concluded that a warning about unusual blood clots with low blood platelets should be added to the product information for COVID-19 Vaccine Janssen [15]. EMA stated that the reported combination of blood clots and low blood platelets is very rare, and the overall benefits of COVID-19 Vaccine Janssen in preventing COVID-19 outweigh the risks of side effects.

Effect of SARS-CoV-2 variants of concern on COVID-19 vaccines

There are emerging SARS-CoV-2 variants of concern (VOCs) which have mutations in the spike region that may potentially have an impact on vaccine effectiveness. Many of the vaccine efficacy studies were carried out before the emergence of SARS-CoV-2 VOCs. There is limited information on vaccine escape associated with the current VOCs and, if infection occurs, whether the variants have an impact on severity of disease. It is also unknown whether the variants will have an impact on severity of disease generally, for individuals of different ages and/or with underlying comorbidities, or by vaccine product. In studies that have addressed the variants, there is limited preliminary evidence of reduced vaccine efficacy, in particular for B.1.351 and possibly also for P.1 [16-20]. Infections with variant viruses have been reported in fully-vaccinated individuals [21,22], although the frequency of this and the severity of illness following infection is not yet well-understood. However, data are also emerging which indicate that vaccine efficacy is maintained for B.1.1.7 [18,23,24].

Assessment of the emerging variants’ potential to escape the immunity induced by the currently available vaccines is ongoing. More information on this will be needed as new variants emerge in the future [7] since the situation concerning VOCs is evolving rapidly.

References

Page last updated 26 May 2021