The column is written by Dr. Chandrakant Lahariya (MBBS, MD), a Physician-Epidemiologist and a leading expert on COVID-19 disease and vaccines. In this fortnightly column, Dr. Lahariya picks up various topics and gives you tailored solutions, catering to the health needs of your entire family — kids, adolescents, adults, and senior citizens, and all the other members.
The topics he delves into today are breakthrough infections, Delta Variants, and vaccines for children.
Delta Plus variant has caused the deaths of fully vaccinated people. Does it mean that this vaccine is ineffective on breakthrough variants?
No, that is not the case. We need to remember that none of the vaccines is 100 per cent efficacious. That is applicable for COVID-19 vaccines as well as all traditional vaccines. Vaccines reduce the chance of diseases and deaths to a variable extent, and various clinical trials give insight into the effectiveness of a particular vaccine.
The COVID-19 vaccines have shown 60 percent to 95 per cent efficacy against severe disease and mortality, which essentially means the rate of moderate to severe illness or deaths in vaccinated people will be 60& to 95% less than those unvaccinated.
However, what we need to remember is that even vaccine people may get severe COVID disease, and very rarely deaths are also possible. This does not at all mean that vaccines are not working; it simply means vaccines don’t provide a 100 per cent guarantee. That is why, even after vaccination, people have been asked to follow Covid appropriate behaviour.
Do vaccinated individuals experience long COVID symptoms after a breakthrough infection?
When a person develops COVID-19 after two weeks of being vaccinated, it is called a breakthrough infection. In all likelihood, such infections are likely to be mild, but they too, like any other infection, can manifest after-effects.
A small study from Israel published recently found apparent long COVID-19 in a few health workers who had breakthrough infections. However, majority of them developed mild symptoms. Therefore, people with breakthrough infections also need to be watchful of post COVID symptoms.
How can a person differentiate between a breakthrough infection and the vaccine side effects?
A vaccine breakthrough infection as one in which a nasal swab can detect the SARS-CoV-2 RNA or protein more than 14 days after a person completed the full recommended doses of a COVID-19 vaccine. The adverse events of all vaccines are known. The vaccine cannot cause RT PCR positivity, and therefore if a person is tested COVID-19 positive, it is the infection which is responsible.
The other difference is that in the case of vaccines, adverse events, if they occur, usually take place within 2-3 days of vaccination, while COVID symptoms can develop any time and will aggravate with time. If one suspects COVID-19 infection, person should get tested and if needed, consult a healthcare provider.
What kind of vaccine side-effects are children likely to experience after vaccination?
COVID-19 vaccines have not been used in children younger than 12 years in any part of the world (except in clinical trials). The adverse events in children aged 12 to 17 years are reported to be very similar to those experienced by adults. The most commonly reported side effects include fever, lethargy, pain at the injection site, joint or muscle ache, and headache. In addition, there are reports of some rare myocarditis and pericarditis in adolescents and young adults. Though symptoms are usually similar, children may have a higher intensity of the known adverse events, and the frequency could be higher.
Once the COVID-19 vaccines use in children starts, we will develop a better understanding.
Which COVID-19 vaccines for children will be available in India?
The first COVID 19 vaccines for 12-17 years, named ZyCoV-D manufactured by Zydus Cadila, have been given an Emergency use License in India on 20 Aug 2021. The clinical trials of Covaxin on 2-17 years are also in progress.
Do doses for such vaccines differ for children?
The number of doses and the dosing interval is similar to the adult population for the currently approved COVID-19 vaccines for 12-17 years.
What are the symptoms of the Delta plus variant in children?
There is no difference in disease symptoms in any age group by SARS CoV2 variants. The only significant difference is the higher transmissibility of the delta variant in comparison to all other variants.
How different will the booster shots be compared to the primary vaccine shots we are taking now?
Booster dose merely indicates a vaccine shot administered after completion of the primary schedule, which could be one (J&J) two (Most COVID-19 vaccines) and three (ZyCoV-D) doses. In more epidemiological terms, there has to be at least six months gap between the primary immunization and the next shot to call it a booster dose. Therefore, this nomenclature merely reflects the gap, and the vaccines material remain the same. However, with various types of COVID-19 vaccines available on different platforms (mRNA, DNA, Viral vectored and inactivated) and then mix and match studies being done for these vaccines, it is likely to use a vaccine on different platforms than the preliminary schedule can be used as a booster dose to produce a higher level of antibodies. However, this is an area where we need more evidence.
There is another discourse on the third dose of vaccines to complete the primary immunisation in particular sub-groups such as immunocompromised individuals. Therefore, merely giving a third dose of otherwise two shot vaccine does not mean it is a booster dose.
After how long will the immunity of the current vaccine wane off, and we will need a booster dose?
The short answer is that we do not know yet. There is early evidence that immunity after natural infection may last for really long, at least a year in most cases. However, the early evidence also indicates that the level of antibodies in vaccinated individuals starts declining over the period, specifically after 4 months of the primary vaccination schedule.
However, we do not know for sure if the decline in antibodies means reduced protection. The person could be protected even with limited antibodies due to cell-based immunity. This is an area where more evidence is needed. A few countries have planned to provide booster doses to select population groups to provide additional protection from emerging variants; however, there is not enough evidence to recommend booster shots at a universal level. Moreover, as many people in different settings are yet to receive the first dose of the COVID-19 vaccine, it is unethical to recommend policies to administer booster shot.
Dr Lahariya can be reached at his email [email protected] or at Twitter Handle @DrLahariya
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