Do words like 'vaccine' or 'covid' affect email deliverability?

However, it is important to note that while large-scale filters are less concerned with individual words, specific or custom-configured on-premise spam filters, often found in corporate or government environments, might still implement broad keyword blocking. This can lead to isolated deliverability issues, though it is not indicative of widespread problems across the internet. The overall consensus is that focusing on a strong sender reputation and positive recipient engagement is far more impactful than obsessing over specific content words.

Key findings

• Major mailbox providers: Large-scale spam filters do not typically block emails based solely on words like 'vaccine' or 'covid'.
• Sender reputation: Deliverability is primarily influenced by the sender's reputation, engagement metrics, and proper email authentication (SPF, DKIM, DMARC).
• Custom filters: Some corporate or on-premise filters might have custom rules that block specific keywords, leading to isolated deliverability issues. This is not a widespread issue for general internet mail.
• Recipient behavior: How recipients interact with your emails (opens, clicks, complaints) significantly impacts inbox placement, regardless of content keywords.

Key considerations

• Context is key: The intent and context of your email are more important than individual words. Legitimate information sharing is usually fine.
• Audience awareness: If sending to specific organizations, be aware they might have unique filtering policies.
• Monitor engagement: Pay close attention to your email engagement rates and complaint rates as primary indicators of deliverability health.
• Avoid general 'spam words' myth: While some words historically linked to spam might raise flags, modern filters are far more sophisticated, as discussed in our guide on whether email spam trigger words are still relevant.
• Content best practices: For a broader understanding of how specific content elements can affect email deliverability, consult resources on email spam words to avoid.

The focus for marketers has shifted towards overall sender reputation, recipient engagement, and maintaining clear communication, especially when discussing sensitive topics. Anecdotal evidence suggests that while major ISPs are intelligent, some localized or legacy systems can still pose challenges based on content.

Key opinions

• Historical context: Some marketers recall a time when specific keywords heavily influenced spam filtering.
• Niche filtering: Corporate or organizational filters can be a wild card, capable of implementing custom, overly broad content blocks.
• Focus on user behavior: The consensus is shifting towards recipient engagement and sender reputation as the primary drivers of inbox placement.
• Viagra example: The classic example of keyword blocking (e.g., 'Viagra') is often cited as a reminder of overly aggressive filtering, as detailed in our article on words like 'viagra' triggering spam filters.

Key considerations

• Test content carefully: Marketers should still test their content, especially for sensitive topics or if sending to a diverse range of corporate domains.
• Understand your audience: Knowing the specific filtering tendencies of your audience (e.g., highly regulated industries) is crucial.
• Prioritize sender reputation: Maintaining a strong sender reputation is far more effective than trying to trick filters by avoiding specific words.
• Monitor feedback loops: Pay attention to bounce messages and spam complaints, as they indicate how your content is being received. For insights into maintaining high deliverability during sensitive times, consider content that balances information with audience comfort.

Experts emphasize that genuine emails from reputable senders, even those containing sensitive or controversial terms, are unlikely to be blocked by mainstream filters. The exceptions typically involve custom, localized blocklists or very niche filtering systems implemented by specific organizations, which are not representative of broader email deliverability trends.

Key opinions

• Keyword irrelevance: Modern, large-scale spam filters do not block emails based on specific words like 'vaccine' or 'covid'.
• Sender reputation reigns: The sender's reputation, built over time through consistent good sending practices, is the paramount factor affecting deliverability.
• Engagement is crucial: How recipients interact with emails (opens, clicks, replies, spam complaints) directly informs filtering decisions.
• Authentication importance: Proper implementation of SPF, DKIM, and DMARC is fundamental for establishing trust with mailbox providers.

Key considerations

• Don't chase keywords: Focusing on avoiding specific words is a distraction from the core principles of good deliverability, and why your emails are going to spam.
• Invest in reputation management: Prioritize building and maintaining a strong sender reputation over keyword optimization.
• Monitor DMARC reports: Analyze DMARC reports to understand authentication failures and potential issues affecting deliverability.
• Educate senders: It is important to educate email marketers and content creators that broad keyword-based blocking by major ISPs is a myth. Understanding how email filtering truly works can lead to better strategies.

Documentation consistently points to overall sender behavior and recipient feedback as key metrics for email filtering. For content concerning sensitive issues, the implicit advice is to ensure accuracy, maintain a high level of subscriber relevance, and provide clear opt-out mechanisms to preserve sender reputation.

Key findings

• No explicit keyword lists: Major mailbox provider documentation does not typically provide lists of specific words (like 'vaccine' or 'covid') that trigger spam filters.
• Focus on user signals: Documentation consistently highlights user engagement (opens, clicks, complaints, unsubscribes) as primary factors in deliverability.
• Content best practices: Guidelines emphasize truthful, non-deceptive content, relevance to the subscriber, and clear unsubscribe options.
• Sensitive topics: For sensitive topics, the focus is on providing accurate information, avoiding sensationalism, and ensuring the content aligns with subscriber expectations to prevent complaints.

Key considerations

• Adhere to global standards: Follow general anti-spam regulations (e.g., CAN-SPAM, GDPR) which prioritize consent and clear communication over specific word usage.
• Prioritize clarity and honesty: Ensure your messaging on sensitive topics is clear, factual, and does not mislead recipients. This aligns with Outlook's new sender requirements for trust and transparency.
• Monitor policy changes: Stay updated on any policy changes from ISPs, especially concerning sensitive content during global events.
• User consent: Always ensure explicit consent for sending emails, particularly for potentially sensitive content, to minimize negative feedback. For example, understanding public perception of health messages can inform how you approach communication.