GVN Experts Address What You Need to Know About Variants and Vaccines
Vaccines
1. Can I get COVID-19 after vaccination, and can I still spread the virus?
People are considered fully vaccinated 2 weeks after their second dose in a 2-dose vaccine, such as the Pfizer or Moderna vaccines, or 2 weeks after a single-dose vaccine, such as Johnson & Johnson’s Janssen vaccine. To get efficient protection, neutralizing antibodies and other T cell immunity needs to be induced. After the first vaccination, it takes at least one to three weeks, depending on the age (young people react faster than older people). This protection can be efficiently achieved after two weeks of complete vaccination.
In this context, it is possible to be infected by SARS-CoV-2 if one is in contact with the virus before vaccination has been fully achieved. It is also possible to spread the virus. Despite the high level of vaccine efficacy, a small percentage of fully vaccinated persons would develop symptomatic or asymptomatic infections with SARS-CoV-2. However, breakthrough infections are rare, and just 2% of vaccinated people result in COVID-19 deaths according to the US CDC. With the spread of variants of concern, cases of breakthrough infections need to be monitored in parallel with genomic surveillance of variants of concern.
Recent observational studies conducted in the UK and Israel provide strong evidence that the Pfizer vaccine is effective against SARS‑CoV-2 infection by preventing viral transmission. Importantly, this study demonstrates that a complete vaccination with two doses is required to effectively stop transmission. Further studies will be required with other COVID-19 vaccines.
2. If I had COVID-19, can I get COVID-19 again?
Yes – you can get COVID-19 again, but it is rare.
Natural immunity acquired after COVID-19 infection will last for several months and at least eight months. Also, there is mounting evidence for a persistent cellular immune protection after such infection. A recent study showed that memory B cells continue to mature and strengthen for at least 12 months after the initial infection. It indicates that your immune cells can produce antibodies against the virus. These studies also suggest that vaccine induced immunity is stronger and far more persistent than natural infection induced immunity. Consistent with this, the number of well documented cases of reinfection has remained very low.
However, re-infection with a variant, which is different from the original strain, appears to be occurring more commonly, as recently described in Brazil. With emergence of fast-spreading variants, vaccination will certainly boost immunity and provide protection for individuals recovered from COVID-19.
3. If I receive one of the approved vaccines, how long will that vaccine protect me from getting COVID-19?
It is uncertain how long vaccination will be protective against COVID-19. Recent studies showed that the levels of neutralizing antibodies will decrease over time, but memory cells can be persistent. Since duration of protection will differ from one vaccine to the other and an individual’s immune response, this information will be obtained when the results of the ongoing prospective studies become available.
With the emergence and spread of various variants, a vaccinated person might need a booster dose of vaccine to prolong protection against the original coronavirus strain and newly emerging variants. Currently, vaccine companies are updating their vaccines against variants. Health officials will determine the need for and timing of COVID-19 booster doses.
4. If I had COVID-19, should I still get one of the approved vaccines?
Yes. Although natural infection can induce protective immunity, the level of acquired immunity could be different depending on the individual’s immune system and disease severity. Importantly, the duration of protective immunity is unclear. Therefore, it is highly recommended to get vaccinated for previously infected people with the virus. Vaccination stimulates a “memory” effect and induces good antibody response. This can provide a robust and lasting immunity.
Many different studies agree that the antibody response to the first mRNA vaccine dose in individuals with pre-existing immunity is equal to, or even exceeds, the titers found in naïve individuals after the second dose. These studies suggest that one dose of mRNA vaccine might be sufficient for previously infected people. Certainly, a complete vaccination with two doses will provide robust protection.
5. If my first shot is with one particular manufacturer’s vaccine, can my second shot be with another manufacturer’s vaccine?
Preliminary results from vaccinating people with the AstraZeneca and Pfizer COVID-19 vaccines in Spain showed that this mix-and-match vaccination produced a potent immune response against SARS-CoV-2. The Pfizer vaccine boosted antibody responses remarkably in one-dose AstraZeneca vaccinees. A similar trial conducted in the UK has shown the safety of this vaccination (the results for the vaccine efficacy has not been released).
Because of safety concerns, several European countries are already recommending that some or all people who were given a first dose of AstraZeneca vaccine get another vaccine for their second dose. However, we still need more data to confirm the protective efficacy and safety of this mix-and match vaccination approach.
6. What are the risks associated with the current vaccines? Should we be afraid of long-term effects of the vaccines?
COVID-19 vaccines are safe. Vaccine safety was evaluated in tens of thousands of participants in clinical trials and went through the Food and Drug Administration’s (FDA) rigorous review process. All the approved vaccines met the agency’s scientific standards for safety, effectiveness, and manufacturing quality.
The vaccination campaign has extended worldwide. As more people get vaccinated, a rare case of blood clots has been reported after receiving the AstraZeneca vaccine or Johnson and Johnson vaccine. More specific information can be found at https://gvn.org/covid-19/vaccine-safety/. The World Health Organization (WHO), the European Medicines Agency (EMA), and the UK Regulatory Agency have stated that the benefits of these vaccines still greatly outweighed the risks.
The CDC has received reports of myocarditis and pericarditis in adolescents and young adults after COVID-19 vaccination. There were “relatively few” cases, and they may be entirely unrelated to vaccination. Most cases appear to be mild, and follow-up of cases is ongoing. The agency is currently reviewing these cases. The known and potential benefits of COVID-19 vaccination outweigh the known and potential risks, including the possible risk of myocarditis or pericarditis.
Although monitoring the safety of these vaccines continues, serious side effects that could cause a long-term health problem are extremely unlikely following COVID-19 vaccination. Millions of people have received COVID-19 vaccines, yet no long-term side effects have been detected.
7. If I am pregnant should I get a vaccine?
There is no formal contra-indication to vaccinating pregnant women. COVID-19 in pregnant women can lead to severe consequences for the mother and the fetus. Thus, regulatory agencies recommend to make the decision based on the risk of exposure to the virus. A recent surveillance study showed the safety of mRNA Covid-19 vaccines (Pfizer and Moderna) in pregnant persons. However, a long-term effect of vaccines on pregnancy needs to be continuously evaluated.
GVN Perspective: Pregnancy and COVID-19 Vaccines – March 5, 2021
8. Can I have the second vaccination after 4 weeks or 12 weeks?
For the AstraZeneca vaccine, the clinical trials have shown that vaccine efficacy was 82.4% in the case of a 12-week interval between the two doses as compared with 54.9% for a less than 6-week interval. This supports the UK’s strategy for vaccinating as many people as possible with a single dose due to limited supply. Currently, the WHO recommends an 8 to 12 weeks interval between the two doses of the AstraZeneca vaccine.
Moderna and Pfizer (mRNA based vaccine) recommend their standard protocols, 4 weeks apart and 3 weeks apart, respectively. Scientists for the Pfizer vaccine suggested having the second dose of immunization within 6 weeks after the first immunization (a grace period). The US CDC recommends following the standard protocol for each vaccine, but waiting up to 42 days between doses can be tolerated. According to the results of a small scale UK trial, the Pfizer vaccine generates a significantly more robust antibody response in older people after delaying the second dose to 12 weeks after the first compared to the standard protocol. Further study will be required for verification.
9. Should my children receive a vaccine?
The CDC recommends that everyone 12 years and older should get a COVID-19 vaccination to help protect against the disease. The Pfizer vaccine has been found to be safe and effective in adolescents 12-to 15 years old. Although fewer children have been infected with COVID-19 compared to adults, children can be infected with the virus, get sick, and spread the virus to others. Widespread vaccination, including children, is critical to helping end the pandemic. Vaccination also allows children to participate in various indoor and outdoor activities safely.
GVN Perspective: Vaccine Priorities: Children or Underserved Populations?
GVN Perspective Today
The Novavax U.S. trial found that the efficacy of its vaccine is about 90 percent. The vaccine further showed an efficacy of 100 percent at preventing moderate or severe disease. With this impressive efficacy, the vaccine can be available globally. The protein-based technology used in this vaccine could also be used for boost vaccination with a mix-and-match vaccine approach.
Variants
1. What are the mutations/variants and where did they originate?
Mutations refer to the change in the genomic information (component of DNA or RNA) which synthesize the various components of a virus. Viruses are constantly changing through mutations of their genome. Most of these mutations will remain silent because they do not provide any advantage to the virus for its dissemination; yet some mutations provide an advantage to the virus and thus are adapted for better fitness. Indeed, these genetic variations lead to the emergence of variants, which may have different characteristics (virus’ ability to spread, to cause disease, or to escape the body’s immune response).
The WHO and CDC classified variants into “variants of concern” and “variants of interest”
- A variant of concern is one for which there is evidence of an increase in transmissibility, detrimental change in COVID-19 epidemiology, more severe disease (e.g., increased hospitalizations or deaths), significant reduction in neutralization by antibodies generated during previous infection or vaccination, reduced effectiveness of treatments or vaccines, or diagnostic detection failures.
- A variant of interest is one with specific genetic markers that have been associated with changes to receptor binding, reduced neutralization by antibodies generated against previous infection or vaccination, reduced efficacy of treatments, potential diagnostic impact, or predicted increase in transmissibility or disease severity. The variants are the cause of an increased proportion of cases or unique outbreak clusters with limited prevalence or expansion globally.
GVN Perspective: Update on SARS-CoV-2 Variants – February 5, 2021
GVN Perspective: Emergence and Global Spread of SARS-CoV-2 Variants – January 26, 2021
2. Why is SARS-CoV-2 mutating and will these variants keep mutating?
Mutations arise as a natural by-product of viral replication. Similar to other RNA viruses, SARS-CoV-2 makes mistakes when it copies its RNA genome. These mutations occur over time and SARS-CoV-2 keeps mutating (evolving) to adapt to the host environment. Some of these mutations have been described to emerge in people who are immunosuppressed and therefore mount a sub-optimal response to the virus or people who have received antibodies from another person, as part of a treatment called convalescent serum.
GVN Perspective: Why Do Genes and Mutations Matter in SARS-CoV-2? – May 27, 2020
3. How are the variants spreading and where have they spread to?
The variants are spreading the same way as the original virus. The variants spread by person-to-person transmission routes. These include direct transmission (cough, sneeze, droplet inhalation transmission) and contact transmission (contact with oral, nasal and eye mucous membranes and to the latter by a contaminated surface).
GVN Perspective: How Long Is a SARS-CoV-2 Infected Person Contagious? – October 23, 2020
4. What are the differences between each of the virus variants in terms of spread, severity and mortality?
Epidemiological data have indicated that the variants of concern (Alpha, Beta, Gamma, and Delta) can spread faster than previously known SARS-CoV-2. Specifically, the Alpha variant has shown 30-50% of enhanced transmissibility. Further, the Delta variant is quickly becoming the dominant strain in the UK by outpacing the Alpha variant that was first discovered in southeastern England. UK health officials suggest that the Delta variant is at least 40 percent more infectious. Currently, there is no firm evidence that the UK variant may cause more severe disease. These details have not been demonstrated yet for the other variants, and this is being carefully monitored.
GVN Perspective: Update on SARS-CoV-2 Variants – February 5, 2021
5. If I had COVID-19, can I get a COVID-19 variant?
Epidemiological studies have shown a possibility of reinfection in previously recovered individuals from COVID-19 with certain variants. Age can impact reinfection with COVID-19. According to the WHO, among those above 65 years, the level of protection against reinfection was estimated to be at 50%. In contrast, among younger people, the level of protection against reinfection was nearly 89%.
Particularly, the Beta and Gamma variants are known to be immune escape mutants by evading antibodies from previous infections, thus causing reinfection of recovered individuals from COVID-19. The Delta variant does seem to have an advantage over previously circulating versions of the virus, especially in individuals whose immunity is waning a while after previous infection or vaccination.
Read more:
Brazil covid-19 variant (P.1)
New Scientist
6. I have recovered from COVID-19. Can I still spread the virus or one of the variants?
Most countries recommend isolation of people with COVID-19 for 10 days. This is because infectious virus is rarely detected after 8 days. There is no evidence that infectious virus persists for longer with the variants.
Yet, some patients with severe COVID-19 have shown prolonged duration of virus shedding, up to 20 days after symptom onset. Virus shedding does not mean that you are infectious as prolonged shedding is usually associated with very low levels of virus.
Currently, duration of contagiousness for patients infected by the variants has not been clearly tested. However, it is very likely that, similar to previous SARS-CoV-2, individuals will no longer have contagious variant after 8 days.
GVN Perspective: How Long Is a SARS-CoV-2 Infected Person Contagious? – October 23, 2020
7. Are monoclonal antibody-based drugs effective against the variants?
Monoclonal antibodies to the viral protein have been shown to efficiently block infection of the human cells by the virus. Recent clinical studies have demonstrated their immediate efficacy to treat early stages of the viral infection. In fact, they have even suggested that using such antibodies might allow prevention of COVID-19 in at risk individuals. However, the cost and the IV administration route do presently limit their use.
Regarding their efficacy against variants, it is important to understand that in contrast with vaccines, such monoclonal antibodies are by definition targeting a single component of the viral envelope. Thus, any mutation at this site would abolish the effect of such monoclonal antibodies. This has recently led to the use of a combination of several monoclonal antibodies targeting different components of the viral envelope (such as the casirivimab and imdevimab antibody cocktail). Recent evidence would suggest the efficacy of such an approach against the variants of the UK and South Africa.
8. Do the current COVID-19 tests indicate if I have had a particular variant and do they identify which variant?
No. Current COVID-19 tests cannot detect if a variant is present or not, although some adjusted PCR-based assays have been proposed. This can be done by genomic sequencing analysis. Thus, genetic surveillance will be key to monitor the circulation of these variants.
GVN Perspective: Update on SARS-CoV-2 Variants – February 5, 2021
Vaccines and Variants
1. What is the effectiveness of each vaccine against a particular variant?
Vaccines will generate what is called a “polyclonal antibody response”. This means that the vaccine generates antibodies to many components of the viral proteins, limiting the impact of specific mutations. Depending on the vaccine, they can also generate T-cells, which may be very important to ensure long term protection, preventing severe disease, and possibly containing variant spread.
In vitro laboratory testing showed that the currently available RNA-based vaccines (Pfizer/BioNtech and Moderna) have retained efficacy against the Alpha (B.1.1.7) variant. In contrast, testing has shown that the currently available vaccines have decreased capacity to generate antibodies to neutralize the Beta, Gamma, and Delta variants. However, recent clinical data would also suggest that the RNA-based vaccines show sufficient protection against the variants.
In the U.K. trial, efficacy of the 2-dose Pfizer vaccine was 87.9% against the Delta variant and 93.4% against the Alpha variant; 2-dose AstraZeneca showed 59.8% efficacy against the Delta variant and 66.1% against the Alpha variant.
According to the data from clinical studies, the efficacy of the Novavax vaccine was 90% in the UK with circulation of the Alpha variant and 60% in South Africa with circulation of the Delta variant. The efficacy of the Johnson & Johnson vaccine was 72% in the US and 57% in South Africa.
Breakthrough infection rarely occurred. When looking at the risk of severe disease and hospitalization, the current vaccines seem to offer protection against developing severe COVID-19.
GVN Perspective: Update on SARS-CoV-2 Variants – February 5, 2021
GVN Perspective: Emergence and Global Spread of SARS-CoV-2 Variants – January 26, 2021
2. If the vaccines are able to control the spread of SARS-CoV-2, can the variants still continue to spread and mutate?
Yes – if vaccination is successful, we will likely see fewer variants.
Achieving herd immunity by combining natural infection and vaccination will definitely mitigate the spread of virus. There is much uncertainty as to which percentage of the population should be immunized but it would likely be safe to reach an 80% of population immunization.
Variants arise because RNA viruses make mistakes every time they replicate. If the virus is given lots of opportunity to infect many people, this greatly increases the chance of a variant appearing. As vaccination will reduce the total number of infected people, it will therefore reduce transmission and the appearance of variants will reduce significantly.
