Vaccine questions and answers

With the persistence of the COVID-19 pandemic and concerns that influenza infections may increase the burden on health care systems, WHO recommends that health care workers and older adults be given top priority for the influenza vaccine this year, especially where there is limited supply. Health care workers are at high risk of getting infected through their regular contact with patients and the influenza vaccine will contribute to minimizing absenteeism due to influenza and decrease disruption to the workforce.

Older adults are at much greater risk of severe disease and death from influenza when compared to younger adults, so the vaccine will help decrease the risks for that population.

If the influenza vaccine supply still allows for others to get vaccinated, then individuals with underlying health conditions, pregnant women and children should be prioritized next in no particular order.

The influenza vaccine is the best tool we have for preventing influenza and reducing the risk of serious complications and even death. The effectiveness of the vaccine can vary from one year to another, depending on the types of influenza viruses circulating and how well they match with the vaccine. It also depends on the health status and age of the person vaccinated, as well as time since vaccination. On average, the vaccine prevents around 60% of infections in healthy adults aged 18–64 years. Influenza vaccines become effective about 14 days after vaccination.

Yes. Influenza viruses constantly change and different strains can circulate each year. In addition, people’s immunity against influenza decreases over time. Seasonal influenza vaccines are therefore updated to reflect the most commonly circulating strains each year in order to provide the people who take them the highest possible immunity against these strains.

Yes. Seasonal influenza vaccines have been in use for more than 50 years. They have been administered to millions of people and have a good safety record. Every year, national medicines regulatory authorities carefully examine each influenza vaccine before it is licensed. Systems are in place to monitor and investigate any reports of adverse events following influenza immunization.

No. The purpose of any vaccine is to train the immune system on how to respond if it encounters the real disease in the future. This training does not affect the immune system against other diseases but rather strengthens it against the target disease. This immunity may last for a short period of time or for many years depending on the type of disease and type of vaccine. The influenza vaccine is considered good for one year, after which immunity against the disease decreases.

No, because influenza and COVID-19 are 2 different diseases. But because both respiratory diseases can impact the health of those infected in severe ways, getting immunized against influenza can decrease the impact of this disease on someone who may already be struggling with COVID-19. It is better for patients and health systems to be dealing with one respiratory illness instead of 2.

There are no known medical contraindications to vaccinating persons who have COVID-19. However, to minimize risk of COVID-19 transmission when taking the vaccine, individuals with suspected or confirmed COVID-19 should be isolated and cared for until they are no longer infectious since the act of seeking immunization may increase the spreading of the infection to others. For that reason, these individuals should defer vaccination until they are released from isolation. Afterwards, it is advised that they take the influenza vaccine in order to decrease the possibility of severe disease from influenza.

Yes. There are no known medical contraindications to vaccinating persons who have COVID-19. WHO advises that high-risk groups should take the influenza vaccine during the COVID-19 pandemic in order to decrease the possibility of severe respiratory illness from the co-circulating viruses this influenza season and to decrease the burden on health care systems. This advice is regardless of whether the person has been vaccinated before against influenza, since the influenza strains circulating today may be different from the ones that circulated in previous years.

Most countries are able to provide the influenza vaccine in limited quantities only, which is why WHO advises prioritizing high-risk groups, starting with health care workers and the elderly. Some countries may not have been able to procure the vaccine at all this year.

Whether you are able to find the vaccine or not, you can still decrease the chances of catching or spreading influenza by following the same public health and social measures recommended for COVID-19:

1. Maintain hand hygiene through frequent hand washing with soap and water, or hand sanitizer.
2. Keep a physical distance of at least one metre from others and wear a mask when that is not possible.
3. Observe respiratory etiquette by coughing and sneezing into your elbow.
4. Seek medical advice if you develop respiratory symptoms and especially if you fall within the high-risk category.
5. Self-isolate if you get sick or self-quarantine if you have come into contact with infected individuals.