Fully vaccinated people as likely to spread Delta variant as unvaccinated: Study
LONDON, Oct 29: People inoculated against Covid-19 are just as likely to spread the delta variant of the virus to contacts in their household as those who haven’t taken their shots, a new research has revealed.
According to a UK study published on Thursday in the Lancet infectious diseases journal, people who have received two doses of a Covid-19 vaccine have a lower, but still appreciable, risk of becoming infected with the delta variant when compared to the unvaccinated. Vaccinated people clear the infection more quickly but the peak viral load among them is similar to people who haven’t go their jabs.
Vaccines remain highly effective at preventing severe disease and deaths from Covid-19, but some studies suggest they may be less effective against the delta variant — the current dominant strain worldwide — though the reason for this has not been established yet.
Most Covid-19 transmission is known to occur in households, yet there is limited data on the risk of transmission of the delta variant from vaccinated people with asymptomatic or mild infections in the community.
Professor Ajit Lalvani of Imperial College London, UK, who co-led the study, said: “Vaccines are critical in controlling the pandemic as we know they are very effective at preventing serious illness and death. However, our findings show that vaccination alone is not enough to prevent people from being infected with the delta variant and spreading it in the household settings. The ongoing transmission we are seeing between vaccinated people makes it essential for unvaccinated people to get vaccinated to protect themselves from acquiring infection and severe Covid-19, especially as more people will be spending time inside in close proximity during the winter months. We found that susceptibility to infection increased already within a few months after the second vaccine dose. So, those eligible for a Covid-19 booster shot should get them promptly.”
The new study included 621 participants, identified by the UK contact tracing system, and was carried out between September 2020 and September 2021. All participants had mild Covid-19 illness or were asymptomatic. Demographic and vaccination status information were collected on enrolment, and participants had daily RT-PCR tests to detect infection, regardless of whether or not they had symptoms. This is one of the few studies that have been carried out using such detailed data from real households, offering key insights into how vaccinated people can still be infected with the delta variant and pass it on to others.
In this study, participants were defined as unvaccinated if they had not received a single Covid-19 vaccine dose at least seven days before enrolment, partially vaccinated if they received one dose more than seven days before enrolment, and fully vaccinated if they received two doses more than seven days before taking part in the study.
Risk of transmission based on vaccination status was analysed for household contacts exposed to delta variant index cases (the first detected case in a household). By performing tests on swab samples provided daily by each participant for 14–20 days, changes over time in viral load — the amount of virus in a person’s nose and throat — were estimated by modelling PCR data, enabling comparisons between fully vaccinated cases of delta infection, and unvaccinated cases of delta, alpha, and pre-alpha infection.
A total of 205 household contacts of delta variant index cases were identified, of whom 53 tested positive for Covid-19. Of the 205 contacts, 126 (62%) were fully vaccinated, 39 (19%) had received one dose, and 40 (19%) were not vaccinated. Among household contacts who had received two doses, 25% (31/126 contacts) became infected with the delta variant compared with 38% (15/40) of unvaccinated household contacts.
Among vaccinated contacts infected with the delta variant, the median length of time since vaccination was 101 days, compared to 64 days for uninfected contacts. This suggests that the risk of infection increased within three months of receiving a second vaccine dose, likely due to waning of the protective immunity.
133 participants had their daily viral load trajectories analysed, of whom 49 had pre-alpha and were unvaccinated, 39 had alpha and were unvaccinated, 29 had delta and were fully vaccinated, and 16 had delta and were unvaccinated. Viral load declined more rapidly among the vaccinated people infected with the delta variant (0.95 log10 virus copies/mL/day) compared with unvaccinated people with delta (0.79), alpha (0.82), or pre-alpha (0.69). However, the authors noted that vaccinated people did not record a lower peak viral load than unvaccinated people, which may explain why the delta variant can still spread despite vaccination as people are most infectious during the peak viral load phase.
Dr Anika Singanayagam, the co-lead author of the study, said, “Understanding the extent to which vaccinated people can pass on the delta variant to others is a public health priority. By carrying out repeated and frequent sampling from contacts of Covid-19 cases, we found that vaccinated people can contract and pass on the infection within households, including to vaccinated household members. Our findings provide important insights into the effect of vaccination in the face of new variants, and specifically, why the delta variant is continuing to cause high Covid-19 case numbers around the world, even in countries with high vaccination rates. Continued public health and social measures to curb transmission – such as masking, wearing, social distancing, and testing – thus remain important, even in vaccinated individuals.”
No Nod For Covaxin Yet, WHO Seeks 'Additional Clarifications': Report
GENEVA, Oct 26: The World Health Organisation's technical advisory group on Tuesday sought "additional clarifications" from Bharat Biotech for its COVID-19 vaccine Covaxin to conduct a final "risk-benefit assessment" for Emergency Use Listing of the vaccine.
Hyderabad-based Bharat Biotech, which has developed Covaxin, had submitted EOI (Expression of Interest) to the WHO on April 19 for the vaccine's Emergency Use Listing (EUL).
The technical advisory group met on Tuesday to review data on Covaxin for the emergency use listing of India's indigenously-made vaccine.
"The TAG met today and decided that additional clarifications from the manufacturer are needed to conduct a final EUL risk-benefit assessment for global use of the vaccine," the WHO said in an email response to a question by PTI on the decision regarding the Emergency Use Listing of Covaxin.
"The TAG expects to receive these clarifications from the manufacturer by the end of this week, and aims to reconvene for the final risk-benefit assessment on November 3," it added.
The Technical Advisory Group for Emergency Use Listing (TAG-EUL) is an independent advisory group that provides recommendations to WHO on whether a Covid 19 vaccine can be listed for emergency use under the EUL procedure.
Bharat Biotech's Covaxin and AstraZeneca and Oxford University's Covishield are the two widely used vaccines in India.
The WHO has so far approved Covid-19 vaccines of Pfizer-BioNTech, AstraZeneca-SK Bio/Serum Institute of India, Johnson & Johnson-Janssen, Moderna, and Sinopharm for emergency use.
Last week, the WHO had said it is expecting one additional piece of information from Bharat Biotech regarding Covaxin and emphasised that it has to thoroughly evaluate to ensure vaccines are safe and "cannot cut corners" before recommending a vaccine for emergency use.
Covaxin gets emergency use nod for children aged 2-18 years
NEW DELHI, Oct 12: The Subject Expert Committee (SEC) of the drug regulator has recommended granting an emergency use authorisation to Bharat Biotech's Covaxin for children aged between 2-18. The SEC has submitted its recommendation to the Drugs Controller General of India (DCGI) for final approval.
“After detailed deliberation, the committee recommended for grant of market authorization of the vaccine for the age group of 2 to 18 years for restricted use in an emergency situation," the expert panel said in a statement.
It said that the emergency use authorisation, however, is subject to four conditions.
"The developer of Covaxin will continue the study as per Whole Virion, Inactivated Corona Virus Vaccine the approved clinical trial protocol," SEC added.
Other conditions listed by the expert panel are: The firm should provide updated Prescribing Information/Package Insert (PI), Summary of Product Characteristics (SmPC) and Factsheet; the firm should submit safety data, including the data on AEFI and AESI, with due analysis, every 15 days for the first two months and monthly thereafter and also as per requirement of New Drugs & Clinical Trials Rules, 2019; and the firm should submit risk management plan.
Bharat Biotech had last week submitted Phase 2/3 clinical trials data of children's trials to the DCGI for its verification and subsequent approval for emergency use authorisation (EUA) for the jab.
Bharat Biotech, in a statement, said that this represents one of the first approvals worldwide for COVID-19 vaccines for the 2-18 age group.
"Bharat Biotech sincerely thank the DCGI, Subject Experts Committee, and CDSCO for their expedited review process. We now await further regulatory approvals from the CDSCO prior to product launch and market availability of COVAXIN for Children," it said.
Two doses of Covaxin will be administered to children with a gap of 28 days. For adults, the government has set a gap of 4-6 weeks between the two shots.
Covaxin, indigenously developed by Bharat Biotech in collaboration with the Indian Council of Medical Research (ICMR), is being used on adults in India's ongoing COVID-19 vaccination drive.
This is the second COVID-19 vaccine to get approved for children in India. DGCI had, in August, approved ZyCoV-D for children aged 12 and above as well as adults. However, the rollout has not yet begun.
Loss of Appetite And Other Side Effects Linked With AstraZeneca Vaccine Shot
LONDON, Sept 10: In a recent development, experts have added 4 new side effects that a receipt of AstraZeneca also known as Covishield in India might experience post-vaccination. Side effects of vaccines against deadly coronavirus have been in the limelight ever since the vaccines were first pushed into usage for the common people.
With AstraZeneca's COVID-19 vaccine, these side effects have always been a little more concerning since some of them can actually turn fatal and lead to the urgent need for hospitalisation.
Earlier, some of the recipients of the AstraZeneca vaccine had complained about blood clotting and brain fogging post jab. Now, reports have surfaced which show there are some new side effects that are also linked with AstraZeneca's COVID shots. Let's look at each one of them:
One of the newer side effects of AstraZeneca's is a pain in the arms and legs. Although not everyone who got the jab experienced this uncommon side effect, only a few reports have been registered where the recipients of the Covisheild vaccine jab complained about sudden pain in their joints in the arms and legs.
Another side effect that has been recently added to the already existing list is loss of appetite. According to the reports, some of the AstraZeneca vaccine recipients have reportedly complained about not being able to eat properly after taking the jab or feeling a sense of losing their appetite for a couple of days after getting the vaccine shot.
Experiencing nausea or sudden abdominal pain is also among the 4 new side effects of the Covisheild vaccine dose. According to the experts, a recipient of the Covishield or AstraZeneca COVID-19 vaccine shot may feel certain discomfort in their chest after taking the vaccine shot which can lead to the feeling of vomiting or nausea. This particular side effect is most likely to occur with the first vaccine dose of Covishield or AstraZeneca, rather than the second one.
Flu-like symptoms such as a fever, chills, and body aches are also very common after taking the vaccine shot, but experts have now warned that a Covisheild recipient may also experience symptoms associated with viral influenza.
Above listed side effects linked with the Covishield vaccine are not considered as serious or life-threatening. However, the persistency of these common symptoms can be a bad sign. What are some of the severe side effects of the AstraZeneca vaccine shot or Covishield? Expert says, watch out for these blood clots, seizures, intense headaches, and allergic reactions, post-vaccination.